diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index 2ec2ef3275..0c8f14fbaa 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -1934,13 +1934,13 @@ nsDOMWindowUtils::SendQueryContentEvent(uint32_t aType,
   EventMessage message;
   switch (aType) {
     case QUERY_SELECTED_TEXT:
-      message = NS_QUERY_SELECTED_TEXT;
+      message = eQuerySelectedText;
       break;
     case QUERY_TEXT_CONTENT:
-      message = NS_QUERY_TEXT_CONTENT;
+      message = eQueryTextContent;
       break;
     case QUERY_CARET_RECT:
-      message = NS_QUERY_CARET_RECT;
+      message = eQueryCaretRect;
       break;
     case QUERY_TEXT_RECT:
       message = NS_QUERY_TEXT_RECT;
@@ -1992,10 +1992,10 @@ nsDOMWindowUtils::SendQueryContentEvent(uint32_t aType,
   InitEvent(queryEvent, &pt);
 
   switch (message) {
-    case NS_QUERY_TEXT_CONTENT:
+    case eQueryTextContent:
       queryEvent.InitForQueryTextContent(aOffset, aLength, useNativeLineBreak);
       break;
-    case NS_QUERY_CARET_RECT:
+    case eQueryCaretRect:
       queryEvent.InitForQueryCaretRect(aOffset, useNativeLineBreak);
       break;
     case NS_QUERY_TEXT_RECT:
@@ -2033,7 +2033,7 @@ nsDOMWindowUtils::SendSelectionSetEvent(uint32_t aOffset,
     return NS_ERROR_FAILURE;
   }
 
-  WidgetSelectionEvent selectionEvent(true, NS_SELECTION_SET, widget);
+  WidgetSelectionEvent selectionEvent(true, eSetSelection, widget);
   InitEvent(selectionEvent);
 
   selectionEvent.mOffset = aOffset;
diff --git a/dom/base/nsISelectionController.idl b/dom/base/nsISelectionController.idl
index 01bbc48312..c3b4c77cb0 100644
--- a/dom/base/nsISelectionController.idl
+++ b/dom/base/nsISelectionController.idl
@@ -16,7 +16,7 @@ interface nsIDOMNode;
 interface nsISelection;
 interface nsISelectionDisplay;
 
-[scriptable, uuid(82c3a9df-9bd6-4da2-b561-d85a9eec5caa)]
+[scriptable, uuid(e5238312-2f50-4ec1-8e23-6337f3a67727)]
 interface nsISelectionController : nsISelectionDisplay
 {
    const short SELECTION_NONE=0;
@@ -29,7 +29,8 @@ interface nsISelectionController : nsISelectionDisplay
    const short SELECTION_ACCESSIBILITY=64; // For accessibility API usage
    const short SELECTION_FIND=128;
    const short SELECTION_URLSECONDARY=256;
-   const short NUM_SELECTIONTYPES=10;
+   const short SELECTION_URLSTRIKEOUT=512;
+   const short NUM_SELECTIONTYPES=11;
 
    const short SELECTION_ANCHOR_REGION = 0;
    const short SELECTION_FOCUS_REGION = 1;
diff --git a/dom/base/nsQueryContentEventResult.cpp b/dom/base/nsQueryContentEventResult.cpp
index a882aeeabe..f293ec8911 100644
--- a/dom/base/nsQueryContentEventResult.cpp
+++ b/dom/base/nsQueryContentEventResult.cpp
@@ -19,8 +19,9 @@ NS_INTERFACE_MAP_END
 NS_IMPL_ADDREF(nsQueryContentEventResult)
 NS_IMPL_RELEASE(nsQueryContentEventResult)
 
-nsQueryContentEventResult::nsQueryContentEventResult() :
-  mEventID(0), mSucceeded(false)
+nsQueryContentEventResult::nsQueryContentEventResult()
+  : mEventMessage(eVoidEvent)
+  , mSucceeded(false)
 {
 }
 
@@ -54,20 +55,19 @@ nsQueryContentEventResult::GetTentativeCaretOffset(uint32_t* aOffset)
   return NS_OK;
 }
 
-static bool IsRectEnabled(uint32_t aEventID)
+static bool IsRectEnabled(EventMessage aEventMessage)
 {
-  return aEventID == NS_QUERY_CARET_RECT ||
-         aEventID == NS_QUERY_TEXT_RECT ||
-         aEventID == NS_QUERY_EDITOR_RECT ||
-         aEventID == NS_QUERY_CHARACTER_AT_POINT;
+  return aEventMessage == eQueryCaretRect ||
+         aEventMessage == NS_QUERY_TEXT_RECT ||
+         aEventMessage == NS_QUERY_EDITOR_RECT ||
+         aEventMessage == NS_QUERY_CHARACTER_AT_POINT;
 }
 
 NS_IMETHODIMP
 nsQueryContentEventResult::GetReversed(bool *aReversed)
 {
   NS_ENSURE_TRUE(mSucceeded, NS_ERROR_NOT_AVAILABLE);
-  NS_ENSURE_TRUE(mEventID == NS_QUERY_SELECTED_TEXT,
-                 NS_ERROR_NOT_AVAILABLE);
+  NS_ENSURE_TRUE(mEventMessage == eQuerySelectedText, NS_ERROR_NOT_AVAILABLE);
   *aReversed = mReversed;
   return NS_OK;
 }
@@ -76,7 +76,7 @@ NS_IMETHODIMP
 nsQueryContentEventResult::GetLeft(int32_t *aLeft)
 {
   NS_ENSURE_TRUE(mSucceeded, NS_ERROR_NOT_AVAILABLE);
-  NS_ENSURE_TRUE(IsRectEnabled(mEventID),
+  NS_ENSURE_TRUE(IsRectEnabled(mEventMessage),
                  NS_ERROR_NOT_AVAILABLE);
   *aLeft = mRect.x;
   return NS_OK;
@@ -86,7 +86,7 @@ NS_IMETHODIMP
 nsQueryContentEventResult::GetWidth(int32_t *aWidth)
 {
   NS_ENSURE_TRUE(mSucceeded, NS_ERROR_NOT_AVAILABLE);
-  NS_ENSURE_TRUE(IsRectEnabled(mEventID),
+  NS_ENSURE_TRUE(IsRectEnabled(mEventMessage),
                  NS_ERROR_NOT_AVAILABLE);
   *aWidth = mRect.width;
   return NS_OK;
@@ -96,7 +96,7 @@ NS_IMETHODIMP
 nsQueryContentEventResult::GetTop(int32_t *aTop)
 {
   NS_ENSURE_TRUE(mSucceeded, NS_ERROR_NOT_AVAILABLE);
-  NS_ENSURE_TRUE(IsRectEnabled(mEventID),
+  NS_ENSURE_TRUE(IsRectEnabled(mEventMessage),
                  NS_ERROR_NOT_AVAILABLE);
   *aTop = mRect.y;
   return NS_OK;
@@ -106,7 +106,7 @@ NS_IMETHODIMP
 nsQueryContentEventResult::GetHeight(int32_t *aHeight)
 {
   NS_ENSURE_TRUE(mSucceeded, NS_ERROR_NOT_AVAILABLE);
-  NS_ENSURE_TRUE(IsRectEnabled(mEventID),
+  NS_ENSURE_TRUE(IsRectEnabled(mEventMessage),
                  NS_ERROR_NOT_AVAILABLE);
   *aHeight = mRect.height;
   return NS_OK;
@@ -116,8 +116,8 @@ NS_IMETHODIMP
 nsQueryContentEventResult::GetText(nsAString &aText)
 {
   NS_ENSURE_TRUE(mSucceeded, NS_ERROR_NOT_AVAILABLE);
-  NS_ENSURE_TRUE(mEventID == NS_QUERY_SELECTED_TEXT ||
-                 mEventID == NS_QUERY_TEXT_CONTENT,
+  NS_ENSURE_TRUE(mEventMessage == eQuerySelectedText ||
+                 mEventMessage == eQueryTextContent,
                  NS_ERROR_NOT_AVAILABLE);
   aText = mString;
   return NS_OK;
@@ -126,7 +126,7 @@ nsQueryContentEventResult::GetText(nsAString &aText)
 NS_IMETHODIMP
 nsQueryContentEventResult::GetSucceeded(bool *aSucceeded)
 {
-  NS_ENSURE_TRUE(mEventID != 0, NS_ERROR_NOT_INITIALIZED);
+  NS_ENSURE_TRUE(mEventMessage != eVoidEvent, NS_ERROR_NOT_INITIALIZED);
   *aSucceeded = mSucceeded;
   return NS_OK;
 }
@@ -135,8 +135,8 @@ NS_IMETHODIMP
 nsQueryContentEventResult::GetNotFound(bool *aNotFound)
 {
   NS_ENSURE_TRUE(mSucceeded, NS_ERROR_NOT_AVAILABLE);
-  NS_ENSURE_TRUE(mEventID == NS_QUERY_SELECTED_TEXT ||
-                 mEventID == NS_QUERY_CHARACTER_AT_POINT,
+  NS_ENSURE_TRUE(mEventMessage == eQuerySelectedText ||
+                 mEventMessage == NS_QUERY_CHARACTER_AT_POINT,
                  NS_ERROR_NOT_AVAILABLE);
   *aNotFound = (mOffset == WidgetQueryContentEvent::NOT_FOUND);
   return NS_OK;
@@ -148,7 +148,7 @@ nsQueryContentEventResult::GetTentativeCaretOffsetNotFound(bool* aNotFound)
   if (NS_WARN_IF(!mSucceeded)) {
     return NS_ERROR_NOT_AVAILABLE;
   }
-  if (NS_WARN_IF(mEventID != NS_QUERY_CHARACTER_AT_POINT)) {
+  if (NS_WARN_IF(mEventMessage != NS_QUERY_CHARACTER_AT_POINT)) {
     return NS_ERROR_NOT_AVAILABLE;
   }
   *aNotFound = (mTentativeCaretOffset == WidgetQueryContentEvent::NOT_FOUND);
@@ -159,7 +159,7 @@ void
 nsQueryContentEventResult::SetEventResult(nsIWidget* aWidget,
                                           const WidgetQueryContentEvent &aEvent)
 {
-  mEventID = aEvent.mMessage;
+  mEventMessage = aEvent.mMessage;
   mSucceeded = aEvent.mSucceeded;
   mReversed = aEvent.mReply.mReversed;
   mRect = aEvent.mReply.mRect;
@@ -167,7 +167,7 @@ nsQueryContentEventResult::SetEventResult(nsIWidget* aWidget,
   mTentativeCaretOffset = aEvent.mReply.mTentativeCaretOffset;
   mString = aEvent.mReply.mString;
 
-  if (!IsRectEnabled(mEventID) || !aWidget || !mSucceeded) {
+  if (!IsRectEnabled(mEventMessage) || !aWidget || !mSucceeded) {
     return;
   }
 
diff --git a/dom/base/nsQueryContentEventResult.h b/dom/base/nsQueryContentEventResult.h
index f502456c26..2f9fa4550d 100644
--- a/dom/base/nsQueryContentEventResult.h
+++ b/dom/base/nsQueryContentEventResult.h
@@ -29,7 +29,7 @@ public:
 protected:
   ~nsQueryContentEventResult();
 
-  uint32_t mEventID;
+  mozilla::EventMessage mEventMessage;
 
   uint32_t mOffset;
   uint32_t mTentativeCaretOffset;
diff --git a/dom/events/ContentEventHandler.cpp b/dom/events/ContentEventHandler.cpp
index 88e84ea00e..37e2ae35a0 100644
--- a/dom/events/ContentEventHandler.cpp
+++ b/dom/events/ContentEventHandler.cpp
@@ -796,11 +796,11 @@ nsresult
 ContentEventHandler::HandleQueryContentEvent(WidgetQueryContentEvent* aEvent)
 {
   switch (aEvent->mMessage) {
-    case NS_QUERY_SELECTED_TEXT:
+    case eQuerySelectedText:
       return OnQuerySelectedText(aEvent);
-    case NS_QUERY_TEXT_CONTENT:
+    case eQueryTextContent:
       return OnQueryTextContent(aEvent);
-    case NS_QUERY_CARET_RECT:
+    case eQueryCaretRect:
       return OnQueryCaretRect(aEvent);
     case NS_QUERY_TEXT_RECT:
       return OnQueryTextRect(aEvent);
@@ -808,7 +808,7 @@ ContentEventHandler::HandleQueryContentEvent(WidgetQueryContentEvent* aEvent)
       return OnQueryEditorRect(aEvent);
     case NS_QUERY_CONTENT_STATE:
       return OnQueryContentState(aEvent);
-    case NS_QUERY_SELECTION_AS_TRANSFERABLE:
+    case eQuerySelectionAsTransferable:
       return OnQuerySelectionAsTransferable(aEvent);
     case NS_QUERY_CHARACTER_AT_POINT:
       return OnQueryCharacterAtPoint(aEvent);
diff --git a/dom/events/ContentEventHandler.h b/dom/events/ContentEventHandler.h
index 34e46f0936..2d16a089d0 100644
--- a/dom/events/ContentEventHandler.h
+++ b/dom/events/ContentEventHandler.h
@@ -42,11 +42,11 @@ public:
   // Handle aEvent in the current process.
   nsresult HandleQueryContentEvent(WidgetQueryContentEvent* aEvent);
 
-  // NS_QUERY_SELECTED_TEXT event handler
+  // eQuerySelectedText event handler
   nsresult OnQuerySelectedText(WidgetQueryContentEvent* aEvent);
-  // NS_QUERY_TEXT_CONTENT event handler
+  // eQueryTextContent event handler
   nsresult OnQueryTextContent(WidgetQueryContentEvent* aEvent);
-  // NS_QUERY_CARET_RECT event handler
+  // eQueryCaretRect event handler
   nsresult OnQueryCaretRect(WidgetQueryContentEvent* aEvent);
   // NS_QUERY_TEXT_RECT event handler
   nsresult OnQueryTextRect(WidgetQueryContentEvent* aEvent);
@@ -54,7 +54,7 @@ public:
   nsresult OnQueryEditorRect(WidgetQueryContentEvent* aEvent);
   // NS_QUERY_CONTENT_STATE event handler
   nsresult OnQueryContentState(WidgetQueryContentEvent* aEvent);
-  // NS_QUERY_SELECTION_AS_TRANSFERABLE event handler
+  // eQuerySelectionAsTransferable event handler
   nsresult OnQuerySelectionAsTransferable(WidgetQueryContentEvent* aEvent);
   // NS_QUERY_CHARACTER_AT_POINT event handler
   nsresult OnQueryCharacterAtPoint(WidgetQueryContentEvent* aEvent);
diff --git a/dom/events/EventNameList.h b/dom/events/EventNameList.h
index 4a943e2c19..de455abb21 100644
--- a/dom/events/EventNameList.h
+++ b/dom/events/EventNameList.h
@@ -649,11 +649,11 @@ NON_IDL_EVENT(DOMFocusOut,
               eUIEventClass)
                                   
 NON_IDL_EVENT(DOMMouseScroll,
-              NS_MOUSE_SCROLL,
+              eLegacyMouseLineOrPageScroll,
               EventNameType_HTMLXUL,
               eMouseScrollEventClass)
 NON_IDL_EVENT(MozMousePixelScroll,
-              NS_MOUSE_PIXEL_SCROLL,
+              eLegacyMousePixelScroll,
               EventNameType_HTMLXUL,
               eMouseScrollEventClass)
                                                 
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index ce36606cbc..7c7b12ee89 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -759,7 +759,7 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
         InitLineOrPageDelta(aTargetFrame, this, wheelEvent);
     }
     break;
-  case NS_SELECTION_SET:
+  case eSetSelection:
     IMEStateManager::HandleSelectionEvent(aPresContext, GetFocusedContent(),
                                           aEvent->AsSelectionEvent());
     break;
@@ -784,7 +784,7 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
       // If the event is trusted event, set the selected text to data of
       // composition event.
       WidgetCompositionEvent* compositionEvent = aEvent->AsCompositionEvent();
-      WidgetQueryContentEvent selectedText(true, NS_QUERY_SELECTED_TEXT,
+      WidgetQueryContentEvent selectedText(true, eQuerySelectedText,
                                            compositionEvent->widget);
       HandleQueryContentEvent(&selectedText);
       NS_ASSERTION(selectedText.mSucceeded, "Failed to get selected text");
@@ -801,9 +801,9 @@ void
 EventStateManager::HandleQueryContentEvent(WidgetQueryContentEvent* aEvent)
 {
   switch (aEvent->mMessage) {
-    case NS_QUERY_SELECTED_TEXT:
-    case NS_QUERY_TEXT_CONTENT:
-    case NS_QUERY_CARET_RECT:
+    case eQuerySelectedText:
+    case eQueryTextContent:
+    case eQueryCaretRect:
     case NS_QUERY_TEXT_RECT:
     case NS_QUERY_EDITOR_RECT:
       if (!IsTargetCrossProcess(aEvent)) {
@@ -814,7 +814,7 @@ EventStateManager::HandleQueryContentEvent(WidgetQueryContentEvent* aEvent)
       return;
     // Following events have not been supported in e10s mode yet.
     case NS_QUERY_CONTENT_STATE:
-    case NS_QUERY_SELECTION_AS_TRANSFERABLE:
+    case eQuerySelectionAsTransferable:
     case NS_QUERY_CHARACTER_AT_POINT:
     case NS_QUERY_DOM_WIDGET_HITTEST:
       break;
@@ -2209,8 +2209,8 @@ EventStateManager::SendLineScrollEvent(nsIFrame* aTargetFrame,
     targetContent = targetContent->GetParent();
   }
 
-  WidgetMouseScrollEvent event(aEvent->mFlags.mIsTrusted, NS_MOUSE_SCROLL,
-                               aEvent->widget);
+  WidgetMouseScrollEvent event(aEvent->mFlags.mIsTrusted,
+                               eLegacyMouseLineOrPageScroll, aEvent->widget);
   event.mFlags.mDefaultPrevented = aState.mDefaultPrevented;
   event.mFlags.mDefaultPreventedByContent = aState.mDefaultPreventedByContent;
   event.refPoint = aEvent->refPoint;
@@ -2249,8 +2249,8 @@ EventStateManager::SendPixelScrollEvent(nsIFrame* aTargetFrame,
     targetContent = targetContent->GetParent();
   }
 
-  WidgetMouseScrollEvent event(aEvent->mFlags.mIsTrusted, NS_MOUSE_PIXEL_SCROLL,
-                               aEvent->widget);
+  WidgetMouseScrollEvent event(aEvent->mFlags.mIsTrusted,
+                               eLegacyMousePixelScroll, aEvent->widget);
   event.mFlags.mDefaultPrevented = aState.mDefaultPrevented;
   event.mFlags.mDefaultPreventedByContent = aState.mDefaultPreventedByContent;
   event.refPoint = aEvent->refPoint;
@@ -3101,8 +3101,8 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
           break;
         }
         case WheelPrefs::ACTION_HISTORY: {
-          // If this event doesn't cause NS_MOUSE_SCROLL event or the direction
-          // is oblique, don't perform history back/forward.
+          // If this event doesn't cause eLegacyMouseLineOrPageScroll event or
+          // the direction is oblique, don't perform history back/forward.
           int32_t intDelta = wheelEvent->GetPreferredIntDelta();
           if (!intDelta) {
             break;
@@ -3111,8 +3111,8 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
           break;
         }
         case WheelPrefs::ACTION_ZOOM: {
-          // If this event doesn't cause NS_MOUSE_SCROLL event or the direction
-          // is oblique, don't perform zoom in/out.
+          // If this event doesn't cause eLegacyMouseLineOrPageScroll event or
+          // the direction is oblique, don't perform zoom in/out.
           int32_t intDelta = wheelEvent->GetPreferredIntDelta();
           if (!intDelta) {
             break;
diff --git a/dom/events/EventStateManager.h b/dom/events/EventStateManager.h
index bc9fa63edc..5eedf7dc49 100644
--- a/dom/events/EventStateManager.h
+++ b/dom/events/EventStateManager.h
@@ -109,8 +109,8 @@ public:
                            nsEventStatus* aStatus);
 
   /**
-   * DispatchLegacyMouseScrollEvents() dispatches NS_MOUSE_SCROLL event and
-   * NS_MOUSE_PIXEL_SCROLL event for compatiblity with old Gecko.
+   * DispatchLegacyMouseScrollEvents() dispatches eLegacyMouseLineOrPageScroll
+   * event and eLegacyMousePixelScroll event for compatibility with old Gecko.
    */
   void DispatchLegacyMouseScrollEvents(nsIFrame* aTargetFrame,
                                        WidgetWheelEvent* aEvent,
diff --git a/dom/events/IMEContentObserver.cpp b/dom/events/IMEContentObserver.cpp
index f5a2479d00..20ecd6f524 100644
--- a/dom/events/IMEContentObserver.cpp
+++ b/dom/events/IMEContentObserver.cpp
@@ -51,20 +51,20 @@ static const char*
 ToChar(EventMessage aEventMessage)
 {
   switch (aEventMessage) {
-    case NS_QUERY_SELECTED_TEXT:
-      return "NS_QUERY_SELECTED_TEXT";
-    case NS_QUERY_TEXT_CONTENT:
-      return "NS_QUERY_TEXT_CONTENT";
-    case NS_QUERY_CARET_RECT:
-      return "NS_QUERY_CARET_RECT";
+    case eQuerySelectedText:
+      return "eQuerySelectedText";
+    case eQueryTextContent:
+      return "eQueryTextContent";
+    case eQueryCaretRect:
+      return "eQueryCaretRect";
     case NS_QUERY_TEXT_RECT:
       return "NS_QUERY_TEXT_RECT";
     case NS_QUERY_EDITOR_RECT:
       return "NS_QUERY_EDITOR_RECT";
     case NS_QUERY_CONTENT_STATE:
       return "NS_QUERY_CONTENT_STATE";
-    case NS_QUERY_SELECTION_AS_TRANSFERABLE:
-      return "NS_QUERY_SELECTION_AS_TRANSFERABLE";
+    case eQuerySelectionAsTransferable:
+      return "eQuerySelectionAsTransferable";
     case NS_QUERY_CHARACTER_AT_POINT:
       return "NS_QUERY_CHARACTER_AT_POINT";
     case NS_QUERY_DOM_WIDGET_HITTEST:
@@ -569,8 +569,7 @@ IMEContentObserver::HandleQueryContentEvent(WidgetQueryContentEvent* aEvent)
 
   // If the instance has cache, it should use the cached selection which was
   // sent to the widget.
-  if (aEvent->mMessage == NS_QUERY_SELECTED_TEXT &&
-      aEvent->mUseNativeLineBreak &&
+  if (aEvent->mMessage == eQuerySelectedText && aEvent->mUseNativeLineBreak &&
       mSelectionData.IsValid()) {
     aEvent->mReply.mContentsRoot = mRootContent;
     aEvent->mReply.mHasSelection = !mSelectionData.IsCollapsed();
@@ -1109,7 +1108,7 @@ IMEContentObserver::UpdateSelectionCache()
 
   // XXX Cannot we cache some information for reducing the cost to compute
   //     selection offset and writing mode?
-  WidgetQueryContentEvent selection(true, NS_QUERY_SELECTED_TEXT, mWidget);
+  WidgetQueryContentEvent selection(true, eQuerySelectedText, mWidget);
   ContentEventHandler handler(GetPresContext());
   handler.OnQuerySelectedText(&selection);
   if (NS_WARN_IF(!selection.mSucceeded)) {
diff --git a/dom/events/IMEStateManager.cpp b/dom/events/IMEStateManager.cpp
index 253da56a8e..d9231f6d11 100644
--- a/dom/events/IMEStateManager.cpp
+++ b/dom/events/IMEStateManager.cpp
@@ -149,8 +149,8 @@ GetEventMessageName(EventMessage aMessage)
       return "NS_COMPOSITION_COMMIT_AS_IS";
     case NS_COMPOSITION_COMMIT:
       return "NS_COMPOSITION_COMMIT";
-    case NS_SELECTION_SET:
-      return "NS_SELECTION_SET";
+    case eSetSelection:
+      return "eSetSelection";
     default:
       return "unacceptable event message";
   }
diff --git a/dom/events/TextComposition.cpp b/dom/events/TextComposition.cpp
index 19946b980f..79458fd5e5 100644
--- a/dom/events/TextComposition.cpp
+++ b/dom/events/TextComposition.cpp
@@ -415,9 +415,7 @@ TextComposition::NotityUpdateComposition(
   if (aCompositionEvent->mMessage == NS_COMPOSITION_START) {
     nsCOMPtr<nsIWidget> widget = mPresContext->GetRootWidget();
     // Update composition start offset
-    WidgetQueryContentEvent selectedTextEvent(true,
-                                              NS_QUERY_SELECTED_TEXT,
-                                              widget);
+    WidgetQueryContentEvent selectedTextEvent(true, eQuerySelectedText, widget);
     widget->DispatchEvent(&selectedTextEvent, status);
     if (selectedTextEvent.mSucceeded) {
       mCompositionStartOffset = selectedTextEvent.mReply.mOffset;
@@ -615,8 +613,7 @@ TextComposition::CompositionEventDispatcher::Run()
   switch (mEventMessage) {
     case NS_COMPOSITION_START: {
       WidgetCompositionEvent compStart(true, NS_COMPOSITION_START, widget);
-      WidgetQueryContentEvent selectedText(true, NS_QUERY_SELECTED_TEXT,
-                                           widget);
+      WidgetQueryContentEvent selectedText(true, eQuerySelectedText, widget);
       ContentEventHandler handler(presContext);
       handler.OnQuerySelectedText(&selectedText);
       NS_ASSERTION(selectedText.mSucceeded, "Failed to get selected text");
diff --git a/dom/html/nsGenericHTMLElement.cpp b/dom/html/nsGenericHTMLElement.cpp
index ea930d9750..5e7d8a1165 100644
--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -2458,8 +2458,8 @@ nsGenericHTMLFormElement::IsElementDisabledForEvents(EventMessage aMessage,
     case ePointerEnter:
     case ePointerLeave:
     case NS_WHEEL_WHEEL:
-    case NS_MOUSE_SCROLL:
-    case NS_MOUSE_PIXEL_SCROLL:
+    case eLegacyMouseLineOrPageScroll:
+    case eLegacyMousePixelScroll:
       return false;
     default:
       break;
diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index 23f784cb76..0ed12e5745 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -2334,7 +2334,7 @@ TabParent::HandleQueryContentEvent(WidgetQueryContentEvent& aEvent)
   }
   switch (aEvent.mMessage) {
     case NS_QUERY_TEXT_RECT:
-    case NS_QUERY_CARET_RECT:
+    case eQueryCaretRect:
     case NS_QUERY_EDITOR_RECT:
       aEvent.mReply.mRect -= GetChildProcessOffset();
       break;
diff --git a/dom/plugins/base/nsPluginInstanceOwner.cpp b/dom/plugins/base/nsPluginInstanceOwner.cpp
index 503e454b7e..c5c0540f0b 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -1812,7 +1812,7 @@ CocoaEventTypeForEvent(const WidgetGUIEvent& anEvent, nsIFrame* aObjectFrame)
     case eFocus:
     case eBlur:
       return NPCocoaEventFocusChanged;
-    case NS_MOUSE_SCROLL:
+    case eLegacyMouseLineOrPageScroll:
       return NPCocoaEventScrollWheel;
     default:
       return (NPCocoaEventType)0;
@@ -1829,7 +1829,7 @@ TranslateToNPCocoaEvent(WidgetGUIEvent* anEvent, nsIFrame* aObjectFrame)
   if (anEvent->mMessage == eMouseMove ||
       anEvent->mMessage == eMouseDown ||
       anEvent->mMessage == eMouseUp ||
-      anEvent->mMessage == NS_MOUSE_SCROLL ||
+      anEvent->mMessage == eLegacyMouseLineOrPageScroll ||
       anEvent->mMessage == eMouseOver ||
       anEvent->mMessage == eMouseOut)
   {
@@ -1871,14 +1871,14 @@ TranslateToNPCocoaEvent(WidgetGUIEvent* anEvent, nsIFrame* aObjectFrame)
       }
       break;
     }
-    case NS_MOUSE_SCROLL:
-    {
+    case eLegacyMouseLineOrPageScroll: {
       WidgetWheelEvent* wheelEvent = anEvent->AsWheelEvent();
       if (wheelEvent) {
         cocoaEvent.data.mouse.deltaX = wheelEvent->lineOrPageDeltaX;
         cocoaEvent.data.mouse.deltaY = wheelEvent->lineOrPageDeltaY;
       } else {
-        NS_WARNING("NS_MOUSE_SCROLL is not a WidgetWheelEvent? (could be, haven't checked)");
+        NS_WARNING("eLegacyMouseLineOrPageScroll is not a WidgetWheelEvent? "
+                   "(could be, haven't checked)");
       }
       break;
     }
diff --git a/gfx/thebes/gfxFont.cpp b/gfx/thebes/gfxFont.cpp
index b16f1746a8..02d7ab48b8 100644
--- a/gfx/thebes/gfxFont.cpp
+++ b/gfx/thebes/gfxFont.cpp
@@ -2081,8 +2081,8 @@ gfxFont::IsSpaceGlyphInvisible(gfxContext *aRefContext, gfxTextRun *aTextRun)
             GetOrCreateGlyphExtents(aTextRun->GetAppUnitsPerDevUnit());
         gfxRect glyphExtents;
         mFontEntry->mSpaceGlyphIsInvisible =
-            extents->GetTightGlyphExtentsAppUnits(this, eHorizontal,
-                aRefContext, GetSpaceGlyph(), &glyphExtents) &&
+            extents->GetTightGlyphExtentsAppUnits(this, aRefContext,
+                GetSpaceGlyph(), &glyphExtents) &&
             glyphExtents.IsEmpty();
         mFontEntry->mSpaceGlyphIsInvisibleInitialized = true;
     }
@@ -2189,11 +2189,14 @@ gfxFont::Measure(gfxTextRun *aTextRun,
                 } else {
                     gfxRect glyphRect;
                     if (!extents->GetTightGlyphExtentsAppUnits(this,
-                            orientation,
                             aRefContext, glyphIndex, &glyphRect)) {
                         glyphRect = gfxRect(0, metrics.mBoundingBox.Y(),
                             advance, metrics.mBoundingBox.Height());
                     }
+                    if (orientation == eVertical) {
+                        Swap(glyphRect.x, glyphRect.y);
+                        Swap(glyphRect.width, glyphRect.height);
+                    }
                     if (isRTL) {
                         glyphRect -= gfxPoint(advance, 0);
                     }
@@ -2218,13 +2221,16 @@ gfxFont::Measure(gfxTextRun *aTextRun,
                     gfxRect glyphRect;
                     if (glyphData->IsMissing() || !extents ||
                         !extents->GetTightGlyphExtentsAppUnits(this,
-                                orientation,
                                 aRefContext, glyphIndex, &glyphRect)) {
                         // We might have failed to get glyph extents due to
                         // OOM or something
                         glyphRect = gfxRect(0, -metrics.mAscent,
                             advance, metrics.mAscent + metrics.mDescent);
                     }
+                    if (orientation == eVertical) {
+                        Swap(glyphRect.x, glyphRect.y);
+                        Swap(glyphRect.width, glyphRect.height);
+                    }
                     if (isRTL) {
                         glyphRect -= gfxPoint(advance, 0);
                     }
@@ -3108,7 +3114,7 @@ gfxFont::GetOrCreateGlyphExtents(int32_t aAppUnitsPerDevUnit) {
 }
 
 void
-gfxFont::SetupGlyphExtents(gfxContext *aContext, Orientation aOrientation, 
+gfxFont::SetupGlyphExtents(gfxContext *aContext,
                            uint32_t aGlyphID, bool aNeedTight,
                            gfxGlyphExtents *aExtents)
 {
@@ -3134,7 +3140,7 @@ gfxFont::SetupGlyphExtents(gfxContext *aContext, Orientation aOrientation,
     cairo_text_extents_t extents;
     cairo_glyph_extents(aContext->GetCairo(), &glyph, 1, &extents);
 
-    const Metrics& fontMetrics = GetMetrics(aOrientation);
+    const Metrics& fontMetrics = GetMetrics(eHorizontal);
     int32_t appUnitsPerDevUnit = aExtents->GetAppUnitsPerDevUnit();
     if (!aNeedTight && extents.x_bearing >= 0 &&
         extents.y_bearing >= -fontMetrics.maxAscent &&
diff --git a/gfx/thebes/gfxFont.h b/gfx/thebes/gfxFont.h
index 084645b274..3145436bf6 100644
--- a/gfx/thebes/gfxFont.h
+++ b/gfx/thebes/gfxFont.h
@@ -1614,8 +1614,7 @@ public:
     gfxGlyphExtents *GetOrCreateGlyphExtents(int32_t aAppUnitsPerDevUnit);
 
     // You need to call SetupCairoFont on the aCR just before calling this
-    virtual void SetupGlyphExtents(gfxContext *aContext,
-                                   Orientation aOrientation, uint32_t aGlyphID,
+    virtual void SetupGlyphExtents(gfxContext *aContext, uint32_t aGlyphID,
                                    bool aNeedTight, gfxGlyphExtents *aExtents);
 
     // This is called by the default Draw() implementation above.
diff --git a/gfx/thebes/gfxGlyphExtents.cpp b/gfx/thebes/gfxGlyphExtents.cpp
index 16e66353ee..ce5440e499 100644
--- a/gfx/thebes/gfxGlyphExtents.cpp
+++ b/gfx/thebes/gfxGlyphExtents.cpp
@@ -36,7 +36,6 @@ gfxGlyphExtents::~gfxGlyphExtents()
 
 bool
 gfxGlyphExtents::GetTightGlyphExtentsAppUnits(gfxFont *aFont,
-    gfxFont::Orientation aOrientation,
     gfxContext *aContext, uint32_t aGlyphID, gfxRect *aExtents)
 {
     HashEntry *entry = mTightGlyphExtents.GetEntry(aGlyphID);
@@ -50,8 +49,7 @@ gfxGlyphExtents::GetTightGlyphExtentsAppUnits(gfxFont *aFont,
 #ifdef DEBUG_TEXT_RUN_STORAGE_METRICS
             ++gGlyphExtentsSetupLazyTight;
 #endif
-            aFont->SetupGlyphExtents(aContext, aOrientation, aGlyphID, true,
-                                     this);
+            aFont->SetupGlyphExtents(aContext, aGlyphID, true, this);
             entry = mTightGlyphExtents.GetEntry(aGlyphID);
         }
         if (!entry) {
diff --git a/gfx/thebes/gfxGlyphExtents.h b/gfx/thebes/gfxGlyphExtents.h
index cda58a4b8f..14cd57fa59 100644
--- a/gfx/thebes/gfxGlyphExtents.h
+++ b/gfx/thebes/gfxGlyphExtents.h
@@ -63,7 +63,6 @@ public:
     // Returns true on success. Can fail on OOM or when aContext is null
     // and extents were not (successfully) prefetched.
     bool GetTightGlyphExtentsAppUnits(gfxFont *aFont,
-            gfxFont::Orientation aOrientation,
             gfxContext *aContext, uint32_t aGlyphID, gfxRect *aExtents);
 
     void SetContainedGlyphWidthAppUnits(uint32_t aGlyphID, uint16_t aWidth) {
diff --git a/gfx/thebes/gfxTextRun.cpp b/gfx/thebes/gfxTextRun.cpp
index 8782e8bdde..fb63dcd7a1 100644
--- a/gfx/thebes/gfxTextRun.cpp
+++ b/gfx/thebes/gfxTextRun.cpp
@@ -1374,8 +1374,6 @@ gfxTextRun::FetchGlyphExtents(gfxContext *aRefContext)
   
         for (j = start; j < end; ++j) {
             const gfxTextRun::CompressedGlyph *glyphData = &charGlyphs[j];
-            gfxFont::Orientation orientation =
-                IsVertical() ? gfxFont::eVertical : gfxFont::eHorizontal;
             if (glyphData->IsSimpleGlyph()) {
                 // If we're in speed mode, don't set up glyph extents here; we'll
                 // just return "optimistic" glyph bounds later
@@ -1392,7 +1390,7 @@ gfxTextRun::FetchGlyphExtents(gfxContext *aRefContext)
 #ifdef DEBUG_TEXT_RUN_STORAGE_METRICS
                         ++gGlyphExtentsSetupEagerSimple;
 #endif
-                        font->SetupGlyphExtents(aRefContext, orientation,
+                        font->SetupGlyphExtents(aRefContext,
                                                 glyphIndex, false, extents);
                     }
                 }
@@ -1418,7 +1416,7 @@ gfxTextRun::FetchGlyphExtents(gfxContext *aRefContext)
 #ifdef DEBUG_TEXT_RUN_STORAGE_METRICS
                         ++gGlyphExtentsSetupEagerTight;
 #endif
-                        font->SetupGlyphExtents(aRefContext, orientation,
+                        font->SetupGlyphExtents(aRefContext,
                                                 glyphIndex, true, extents);
                     }
                 }
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 126b445895..e074b04b1f 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -7164,7 +7164,7 @@ PresShell::HandleEvent(nsIFrame* aFrame,
       if (presShell != this) {
         nsIFrame* frame = presShell->GetRootFrame();
         if (!frame) {
-          if (aEvent->mMessage == NS_QUERY_TEXT_CONTENT ||
+          if (aEvent->mMessage == eQueryTextContent ||
               aEvent->IsContentCommandEvent()) {
             return NS_OK;
           }
diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index c71b98787c..11e0b84525 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -3019,6 +3019,7 @@ nsFrame::HandlePress(nsPresContext* aPresContext,
       if (curDetail->mType != nsISelectionController::SELECTION_SPELLCHECK &&
           curDetail->mType != nsISelectionController::SELECTION_FIND &&
           curDetail->mType != nsISelectionController::SELECTION_URLSECONDARY &&
+          curDetail->mType != nsISelectionController::SELECTION_URLSTRIKEOUT &&
           curDetail->mStart <= offsets.StartOffset() &&
           offsets.EndOffset() <= curDetail->mEnd)
       {
diff --git a/layout/generic/nsLineLayout.cpp b/layout/generic/nsLineLayout.cpp
index db0baea794..ade505d89a 100644
--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@@ -3285,7 +3285,7 @@ nsLineLayout::RelativePositionFrames(PerSpanData* psd, nsOverflowAreas& aOverflo
         if (pfd->mRecomputeOverflow ||
             frame->StyleContext()->HasTextDecorationLines()) {
           nsTextFrame* f = static_cast<nsTextFrame*>(frame);
-          r = f->RecomputeOverflow(*mBlockReflowState);
+          r = f->RecomputeOverflow(mBlockReflowState->frame);
         }
         frame->FinishAndStoreOverflow(r, frame->GetSize());
       }
diff --git a/layout/generic/nsSelection.cpp b/layout/generic/nsSelection.cpp
index f5bbb91fb2..90f816ffb3 100644
--- a/layout/generic/nsSelection.cpp
+++ b/layout/generic/nsSelection.cpp
@@ -275,6 +275,7 @@ GetIndexFromSelectionType(SelectionType aType)
     case nsISelectionController::SELECTION_ACCESSIBILITY: return 6; break;
     case nsISelectionController::SELECTION_FIND: return 7; break;
     case nsISelectionController::SELECTION_URLSECONDARY: return 8; break;
+    case nsISelectionController::SELECTION_URLSTRIKEOUT: return 9; break;
     default:
       return -1; break;
     }
@@ -296,6 +297,7 @@ GetSelectionTypeFromIndex(int8_t aIndex)
     case 6: return nsISelectionController::SELECTION_ACCESSIBILITY; break;
     case 7: return nsISelectionController::SELECTION_FIND; break;
     case 8: return nsISelectionController::SELECTION_URLSECONDARY; break;
+    case 9: return nsISelectionController::SELECTION_URLSTRIKEOUT; break;
     default:
       return nsISelectionController::SELECTION_NORMAL; break;
   }
diff --git a/layout/generic/nsTextFrame.cpp b/layout/generic/nsTextFrame.cpp
index fdf186ed08..15cf241445 100644
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -354,6 +354,9 @@ public:
     }
   }
 
+  nscolor GetSystemFieldForegroundColor();
+  nscolor GetSystemFieldBackgroundColor();
+
 protected:
   nsTextFrame*   mFrame;
   nsPresContext* mPresContext;
@@ -373,6 +376,8 @@ protected:
 
   int32_t mSufficientContrast;
   nscolor mFrameBackgroundColor;
+  nscolor mSystemFieldForegroundColor;
+  nscolor mSystemFieldBackgroundColor;
 
   // selection colors and underline info, the colors are resolved colors if
   // mResolveColors is true (which is the default), i.e., the foreground color
@@ -3637,6 +3642,11 @@ nsTextPaintStyle::InitCommonColors()
   nscolor defaultBgColor = mPresContext->DefaultBackgroundColor();
   mFrameBackgroundColor = NS_ComposeColors(defaultBgColor, bgColor);
 
+  mSystemFieldForegroundColor =
+    LookAndFeel::GetColor(LookAndFeel::eColorID__moz_fieldtext);
+  mSystemFieldBackgroundColor =
+    LookAndFeel::GetColor(LookAndFeel::eColorID__moz_field);
+
   if (bgFrame->IsThemed()) {
     // Assume a native widget has sufficient contrast always
     mSufficientContrast = 0;
@@ -3664,6 +3674,20 @@ nsTextPaintStyle::InitCommonColors()
   mInitCommonColors = true;
 }
 
+nscolor
+nsTextPaintStyle::GetSystemFieldForegroundColor()
+{
+  InitCommonColors();
+  return mSystemFieldForegroundColor;
+}
+
+nscolor
+nsTextPaintStyle::GetSystemFieldBackgroundColor()
+{
+  InitCommonColors();
+  return mSystemFieldBackgroundColor;
+}
+
 static Element*
 FindElementAncestorForMozSelection(nsIContent* aContent)
 {
@@ -4830,6 +4854,18 @@ LazyGetLineBaselineOffset(nsIFrame* aChildFrame, nsBlockFrame* aBlockFrame)
   }
 }
 
+static bool IsUnderlineRight(nsIFrame* aFrame)
+{
+  nsIAtom* langAtom = aFrame->StyleFont()->mLanguage;
+  if (!langAtom) {
+    return false;
+  }
+  nsAtomString langStr(langAtom);
+  return (StringBeginsWith(langStr, NS_LITERAL_STRING("ja")) ||
+          StringBeginsWith(langStr, NS_LITERAL_STRING("ko"))) &&
+         (langStr.Length() == 2 || langStr[2] == '-');
+}
+
 void
 nsTextFrame::GetTextDecorations(
                     nsPresContext* aPresContext,
@@ -4928,11 +4964,19 @@ nsTextFrame::GetTextDecorations(
         color = nsLayoutUtils::GetColor(f, eCSSProperty_text_decoration_color);
       }
 
-      if (textDecorations & NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE) {
+      bool swapUnderlineAndOverline = vertical && IsUnderlineRight(f);
+      const uint8_t kUnderline =
+        swapUnderlineAndOverline ? NS_STYLE_TEXT_DECORATION_LINE_OVERLINE :
+                                   NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE;
+      const uint8_t kOverline =
+        swapUnderlineAndOverline ? NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE :
+                                   NS_STYLE_TEXT_DECORATION_LINE_OVERLINE;
+
+      if (textDecorations & kUnderline) {
         aDecorations.mUnderlines.AppendElement(
           nsTextFrame::LineDecoration(f, baselineOffset, color, style));
       }
-      if (textDecorations & NS_STYLE_TEXT_DECORATION_LINE_OVERLINE) {
+      if (textDecorations & kOverline) {
         aDecorations.mOverlines.AppendElement(
           nsTextFrame::LineDecoration(f, baselineOffset, color, style));
       }
@@ -4965,6 +5009,12 @@ nsTextFrame::GetTextDecorations(
     if (f->IsFloating() || f->IsAbsolutelyPositioned()) {
       break;
     }
+
+    // If we're an outer <svg> element, which is classified as an atomic
+    // inline-level element, we're done.
+    if (f->GetType() == nsGkAtoms::svgOuterSVGFrame) {
+      break;
+    }
   }
 }
 
@@ -5175,16 +5225,16 @@ nsTextFrame::UnionAdditionalOverflow(nsPresContext* aPresContext,
   AddStateBits(TEXT_SELECTION_UNDERLINE_OVERFLOWED);
 }
 
-static gfxFloat
-ComputeDescentLimitForSelectionUnderline(nsPresContext* aPresContext,
-                                         nsTextFrame* aFrame,
-                                         const gfxFont::Metrics& aFontMetrics)
+gfxFloat
+nsTextFrame::ComputeDescentLimitForSelectionUnderline(
+               nsPresContext* aPresContext,
+               const gfxFont::Metrics& aFontMetrics)
 {
   gfxFloat app = aPresContext->AppUnitsPerDevPixel();
   nscoord lineHeightApp =
-    nsHTMLReflowState::CalcLineHeight(aFrame->GetContent(),
-                                      aFrame->StyleContext(), NS_AUTOHEIGHT,
-                                      aFrame->GetFontSizeInflation());
+    nsHTMLReflowState::CalcLineHeight(GetContent(),
+                                      StyleContext(), NS_AUTOHEIGHT,
+                                      GetFontSizeInflation());
   gfxFloat lineHeight = gfxFloat(lineHeightApp) / app;
   if (lineHeight <= aFontMetrics.maxHeight) {
     return aFontMetrics.maxDescent;
@@ -5196,15 +5246,18 @@ ComputeDescentLimitForSelectionUnderline(nsPresContext* aPresContext,
 // Make sure this stays in sync with DrawSelectionDecorations below
 static const SelectionType SelectionTypesWithDecorations =
   nsISelectionController::SELECTION_SPELLCHECK |
+  nsISelectionController::SELECTION_URLSTRIKEOUT |
   nsISelectionController::SELECTION_IME_RAWINPUT |
   nsISelectionController::SELECTION_IME_SELECTEDRAWTEXT |
   nsISelectionController::SELECTION_IME_CONVERTEDTEXT |
   nsISelectionController::SELECTION_IME_SELECTEDCONVERTEDTEXT;
 
-static gfxFloat
-ComputeSelectionUnderlineHeight(nsPresContext* aPresContext,
-                                const gfxFont::Metrics& aFontMetrics,
-                                SelectionType aSelectionType)
+/* static */
+gfxFloat
+nsTextFrame::ComputeSelectionUnderlineHeight(
+               nsPresContext* aPresContext,
+               const gfxFont::Metrics& aFontMetrics,
+               SelectionType aSelectionType)
 {
   switch (aSelectionType) {
     case nsISelectionController::SELECTION_IME_RAWINPUT:
@@ -5232,28 +5285,22 @@ ComputeSelectionUnderlineHeight(nsPresContext* aPresContext,
   }
 }
 
-enum DecorationType {
-  eNormalDecoration,
-  eSelectionDecoration
-};
-
-static void
-PaintDecorationLine(nsIFrame* aFrame,
-                    gfxContext* const aCtx,
-                    const gfxRect& aDirtyRect,
-                    nscolor aColor,
-                    const nscolor* aOverrideColor,
-                    const gfxPoint& aPt,
-                    gfxFloat aICoordInFrame,
-                    const gfxSize& aLineSize,
-                    gfxFloat aAscent,
-                    gfxFloat aOffset,
-                    uint8_t aDecoration,
-                    uint8_t aStyle,
-                    DecorationType aDecorationType,
-                    nsTextFrame::DrawPathCallbacks* aCallbacks,
-                    bool aVertical,
-                    gfxFloat aDescentLimit = -1.0)
+void
+nsTextFrame::PaintDecorationLine(gfxContext* const aCtx,
+                                 const gfxRect& aDirtyRect,
+                                 nscolor aColor,
+                                 const nscolor* aOverrideColor,
+                                 const gfxPoint& aPt,
+                                 gfxFloat aICoordInFrame,
+                                 const gfxSize& aLineSize,
+                                 gfxFloat aAscent,
+                                 gfxFloat aOffset,
+                                 uint8_t aDecoration,
+                                 uint8_t aStyle,
+                                 DecorationType aDecorationType,
+                                 DrawPathCallbacks* aCallbacks,
+                                 bool aVertical,
+                                 gfxFloat aDescentLimit /* = -1.0 */)
 {
   nscolor lineColor = aOverrideColor ? *aOverrideColor : aColor;
   if (aCallbacks) {
@@ -5262,7 +5309,7 @@ PaintDecorationLine(nsIFrame* aFrame,
     } else {
       aCallbacks->NotifyBeforeSelectionDecorationLine(lineColor);
     }
-    nsCSSRendering::DecorationLineToPath(aFrame, aCtx, aDirtyRect, lineColor,
+    nsCSSRendering::DecorationLineToPath(this, aCtx, aDirtyRect, lineColor,
       aPt, aICoordInFrame, aLineSize, aAscent, aOffset, aDecoration, aStyle,
       aVertical, aDescentLimit);
     if (aDecorationType == eNormalDecoration) {
@@ -5271,7 +5318,7 @@ PaintDecorationLine(nsIFrame* aFrame,
       aCallbacks->NotifySelectionDecorationLinePathEmitted();
     }
   } else {
-    nsCSSRendering::PaintDecorationLine(aFrame, *aCtx->GetDrawTarget(),
+    nsCSSRendering::PaintDecorationLine(this, *aCtx->GetDrawTarget(),
                                         ToRect(aDirtyRect), lineColor,
       aPt, Float(aICoordInFrame), aLineSize, aAscent, aOffset, aDecoration, aStyle,
       aVertical, aDescentLimit);
@@ -5282,16 +5329,20 @@ PaintDecorationLine(nsIFrame* aFrame,
  * This, plus SelectionTypesWithDecorations, encapsulates all knowledge about
  * drawing text decoration for selections.
  */
-static void DrawSelectionDecorations(gfxContext* aContext,
-    const gfxRect& aDirtyRect,
-    SelectionType aType,
-    nsTextFrame* aFrame,
-    nsTextPaintStyle& aTextPaintStyle,
-    const TextRangeStyle &aRangeStyle,
-    const gfxPoint& aPt, gfxFloat aICoordInFrame, gfxFloat aWidth,
-    gfxFloat aAscent, const gfxFont::Metrics& aFontMetrics,
-    nsTextFrame::DrawPathCallbacks* aCallbacks,
-    bool aVertical)
+void
+nsTextFrame::DrawSelectionDecorations(gfxContext* aContext,
+                                      const gfxRect& aDirtyRect,
+                                      SelectionType aType,
+                                      nsTextPaintStyle& aTextPaintStyle,
+                                      const TextRangeStyle &aRangeStyle,
+                                      const gfxPoint& aPt,
+                                      gfxFloat aICoordInFrame,
+                                      gfxFloat aWidth,
+                                      gfxFloat aAscent,
+                                      const gfxFont::Metrics& aFontMetrics,
+                                      DrawPathCallbacks* aCallbacks,
+                                      bool aVertical,
+                                      uint8_t aDecoration)
 {
   gfxPoint pt(aPt);
   gfxSize size(aWidth,
@@ -5299,7 +5350,7 @@ static void DrawSelectionDecorations(gfxContext* aContext,
                                                aFontMetrics, aType));
   gfxFloat descentLimit =
     ComputeDescentLimitForSelectionUnderline(aTextPaintStyle.PresContext(),
-                                             aFrame, aFontMetrics);
+                                             aFontMetrics);
 
   float relativeSize;
   uint8_t style;
@@ -5310,6 +5361,9 @@ static void DrawSelectionDecorations(gfxContext* aContext,
     aTextPaintStyle.GetSelectionUnderlineForPaint(index, &color,
                                                   &relativeSize, &style);
 
+  gfxFloat offset = aDecoration == NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE ?
+                      aFontMetrics.underlineOffset : aFontMetrics.maxAscent;
+
   switch (aType) {
     case nsISelectionController::SELECTION_IME_RAWINPUT:
     case nsISelectionController::SELECTION_IME_SELECTEDRAWTEXT:
@@ -5342,13 +5396,25 @@ static void DrawSelectionDecorations(gfxContext* aContext,
           // There is no underline style definition.
           return;
         }
-        if (aRangeStyle.IsUnderlineColorDefined()) {
+        // If underline color is defined and that doesn't depend on the
+        // foreground color, we should use the color directly.
+        if (aRangeStyle.IsUnderlineColorDefined() &&
+            aRangeStyle.IsForegroundColorDefined() &&
+            aRangeStyle.mUnderlineColor != aRangeStyle.mForegroundColor) {
           color = aRangeStyle.mUnderlineColor;
-        } else if (aRangeStyle.IsForegroundColorDefined()) {
-          color = aRangeStyle.mForegroundColor;
-        } else {
-          NS_ASSERTION(!aRangeStyle.IsBackgroundColorDefined(),
-                       "Only the background color is defined");
+        }
+        // If foreground color or background color is defined, the both colors
+        // are computed by GetSelectionTextColors().  Then, we should use its
+        // foreground color always.  The color should have sufficient contrast
+        // with the background color.
+        else if (aRangeStyle.IsForegroundColorDefined() ||
+                 aRangeStyle.IsBackgroundColorDefined()) {
+          nscolor bg;
+          GetSelectionTextColors(aType, aTextPaintStyle, aRangeStyle,
+                                 &color, &bg);
+        }
+        // Otherwise, use the foreground color of the frame.
+        else {
           color = aTextPaintStyle.GetTextColor();
         }
       } else if (!weDefineSelectionUnderline) {
@@ -5362,30 +5428,37 @@ static void DrawSelectionDecorations(gfxContext* aContext,
       if (!weDefineSelectionUnderline)
         return;
       break;
+    case nsISelectionController::SELECTION_URLSTRIKEOUT: {
+      nscoord inflationMinFontSize =
+        nsLayoutUtils::InflationMinFontSizeFor(this);
+      float inflation =
+        GetInflationForTextDecorations(this, inflationMinFontSize);
+      const gfxFont::Metrics metrics =
+        GetFirstFontMetrics(GetFontGroupForFrame(this, inflation), aVertical);
+
+      relativeSize = 2.0f;
+      offset = metrics.strikeoutOffset + 0.5;
+      aDecoration = NS_STYLE_TEXT_DECORATION_LINE_LINE_THROUGH;
+      break;
+    }
     default:
       NS_WARNING("Requested selection decorations when there aren't any");
       return;
   }
   size.height *= relativeSize;
-  PaintDecorationLine(aFrame, aContext, aDirtyRect, color, nullptr, pt,
+  PaintDecorationLine(aContext, aDirtyRect, color, nullptr, pt,
     (aVertical ? (pt.y - aPt.y) : (pt.x - aPt.x)) + aICoordInFrame,
-    size, aAscent, aFontMetrics.underlineOffset,
-    NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE, style, eSelectionDecoration,
+    size, aAscent, offset, aDecoration, style, eSelectionDecoration,
     aCallbacks, aVertical, descentLimit);
 }
 
-/**
- * This function encapsulates all knowledge of how selections affect foreground
- * and background colors.
- * @return true if the selection affects colors, false otherwise
- * @param aForeground the foreground color to use
- * @param aBackground the background color to use, or RGBA(0,0,0,0) if no
- * background should be painted
- */
-static bool GetSelectionTextColors(SelectionType aType,
-                                     nsTextPaintStyle& aTextPaintStyle,
-                                     const TextRangeStyle &aRangeStyle,
-                                     nscolor* aForeground, nscolor* aBackground)
+/* static */
+bool
+nsTextFrame::GetSelectionTextColors(SelectionType aType,
+                                    nsTextPaintStyle& aTextPaintStyle,
+                                    const TextRangeStyle &aRangeStyle,
+                                    nscolor* aForeground,
+                                    nscolor* aBackground)
 {
   switch (aType) {
     case nsISelectionController::SELECTION_NORMAL:
@@ -5402,17 +5475,28 @@ static bool GetSelectionTextColors(SelectionType aType,
     case nsISelectionController::SELECTION_IME_CONVERTEDTEXT:
     case nsISelectionController::SELECTION_IME_SELECTEDCONVERTEDTEXT:
       if (aRangeStyle.IsDefined()) {
-        *aForeground = aTextPaintStyle.GetTextColor();
-        *aBackground = NS_RGBA(0,0,0,0);
         if (!aRangeStyle.IsForegroundColorDefined() &&
             !aRangeStyle.IsBackgroundColorDefined()) {
+          *aForeground = aTextPaintStyle.GetTextColor();
+          *aBackground = NS_RGBA(0,0,0,0);
           return false;
         }
         if (aRangeStyle.IsForegroundColorDefined()) {
           *aForeground = aRangeStyle.mForegroundColor;
-        }
-        if (aRangeStyle.IsBackgroundColorDefined()) {
+          if (aRangeStyle.IsBackgroundColorDefined()) {
+            *aBackground = aRangeStyle.mBackgroundColor;
+          } else {
+            // If foreground color is defined but background color isn't
+            // defined, we can guess that IME must expect that the background
+            // color is system's default field background color.
+            *aBackground = aTextPaintStyle.GetSystemFieldBackgroundColor();
+          }
+        } else { // aRangeStyle.IsBackgroundColorDefined() is true
           *aBackground = aRangeStyle.mBackgroundColor;
+          // If background color is defined but foreground color isn't defined,
+          // we can assume that IME must expect that the foreground color is
+          // same as system's field text color.
+          *aForeground = aTextPaintStyle.GetSystemFieldForegroundColor();
         }
         return true;
       }
@@ -5568,6 +5652,9 @@ AddHyphenToMetrics(nsTextFrame* aTextFrame, gfxTextRun* aBaseTextRun,
   gfxTextRun::Metrics hyphenMetrics =
     hyphenTextRun->MeasureText(0, hyphenTextRun->GetLength(),
                                aBoundingBoxType, aContext, nullptr);
+  if (aTextFrame->GetWritingMode().IsLineInverted()) {
+    hyphenMetrics.mBoundingBox.y = -hyphenMetrics.mBoundingBox.YMost();
+  }
   aMetrics->CombineWith(hyphenMetrics, aBaseTextRun->IsRightToLeft());
 }
 
@@ -5832,6 +5919,10 @@ nsTextFrame::PaintTextSelectionDecorations(gfxContext* aCtx,
 
   gfxFont* firstFont = aProvider.GetFontGroup()->GetFirstValidFont();
   bool verticalRun = mTextRun->IsVertical();
+  bool rightUnderline = verticalRun && IsUnderlineRight(this);
+  const uint8_t kDecoration =
+    rightUnderline ? NS_STYLE_TEXT_DECORATION_LINE_OVERLINE :
+                     NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE;
   bool useVerticalMetrics = verticalRun && mTextRun->UseCenterBaseline();
   gfxFont::Metrics
     decorationMetrics(firstFont->GetMetrics(useVerticalMetrics ?
@@ -5875,10 +5966,10 @@ nsTextFrame::PaintTextSelectionDecorations(gfxContext* aCtx,
       }
       gfxFloat width = Abs(advance) / app;
       gfxFloat xInFrame = pt.x - (aFramePt.x / app);
-      DrawSelectionDecorations(aCtx, dirtyRect, aSelectionType, this,
+      DrawSelectionDecorations(aCtx, dirtyRect, aSelectionType,
                                aTextPaintStyle, selectedStyle, pt, xInFrame,
                                width, mAscent / app, decorationMetrics,
-                               aCallbacks, verticalRun);
+                               aCallbacks, verticalRun, kDecoration);
     }
     iterator.UpdateWithAdvance(advance);
   }
@@ -6388,7 +6479,7 @@ nsTextFrame::DrawTextRunAndDecorations(
       decSize.height = metrics.underlineSize;
       bCoord = (frameBStart - dec.mBaselineOffset) / app;
 
-      PaintDecorationLine(this, aCtx, dirtyRect, dec.mColor,
+      PaintDecorationLine(aCtx, dirtyRect, dec.mColor,
         aDecorationOverrideColor, decPt, 0.0, decSize, ascent,
         metrics.underlineOffset, NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE,
         dec.mStyle, eNormalDecoration, aCallbacks, verticalRun);
@@ -6409,7 +6500,7 @@ nsTextFrame::DrawTextRunAndDecorations(
       decSize.height = metrics.underlineSize;
       bCoord = (frameBStart - dec.mBaselineOffset) / app;
 
-      PaintDecorationLine(this, aCtx, dirtyRect, dec.mColor,
+      PaintDecorationLine(aCtx, dirtyRect, dec.mColor,
         aDecorationOverrideColor, decPt, 0.0, decSize, ascent,
         metrics.maxAscent, NS_STYLE_TEXT_DECORATION_LINE_OVERLINE, dec.mStyle,
         eNormalDecoration, aCallbacks, verticalRun);
@@ -6436,7 +6527,7 @@ nsTextFrame::DrawTextRunAndDecorations(
       decSize.height = metrics.strikeoutSize;
       bCoord = (frameBStart - dec.mBaselineOffset) / app;
 
-      PaintDecorationLine(this, aCtx, dirtyRect, dec.mColor,
+      PaintDecorationLine(aCtx, dirtyRect, dec.mColor,
         aDecorationOverrideColor, decPt, 0.0, decSize, ascent,
         metrics.strikeoutOffset, NS_STYLE_TEXT_DECORATION_LINE_LINE_THROUGH,
         dec.mStyle, eNormalDecoration, aCallbacks, verticalRun);
@@ -6647,7 +6738,7 @@ nsTextFrame::CombineSelectionUnderlineRect(nsPresContext* aPresContext,
   gfxFloat underlineOffset = fontGroup->GetUnderlineOffset();
   gfxFloat ascent = aPresContext->AppUnitsToGfxUnits(mAscent);
   gfxFloat descentLimit =
-    ComputeDescentLimitForSelectionUnderline(aPresContext, this, metrics);
+    ComputeDescentLimitForSelectionUnderline(aPresContext, metrics);
 
   SelectionDetails *details = GetSelectionDetails();
   for (SelectionDetails *sd = details; sd; sd = sd->mNext) {
@@ -7654,8 +7745,9 @@ nsTextFrame::AddInlinePrefISizeForFlow(nsRenderingContext *aRenderingContext,
       // XXXldb Shouldn't we be including the newline as part of the
       // segment that it ends rather than part of the segment that it
       // starts?
-      NS_ASSERTION(preformatNewlines,
-                   "We can't be here unless newlines are hard breaks");
+      NS_ASSERTION(preformatNewlines || preformatTabs,
+                   "We can't be here unless newlines are "
+                   "hard breaks or there are tabs");
       preformattedNewline = preformatNewlines && textRun->CharIsNewline(i);
       preformattedTab = preformatTabs && textRun->CharIsTab(i);
       if (!preformattedNewline && !preformattedTab) {
@@ -7799,12 +7891,12 @@ nsTextFrame::ComputeTightBounds(gfxContext* aContext) const
                               ComputeTransformedLength(provider),
                               gfxFont::TIGHT_HINTED_OUTLINE_EXTENTS,
                               aContext, &provider);
+  if (GetWritingMode().IsLineInverted()) {
+    metrics.mBoundingBox.y = -metrics.mBoundingBox.YMost();
+  }
   // mAscent should be the same as metrics.mAscent, but it's what we use to
   // paint so that's the one we'll use.
   nsRect boundingBox = RoundOut(metrics.mBoundingBox);
-  if (GetWritingMode().IsLineInverted()) {
-    boundingBox.y = -boundingBox.YMost();
-  }
   boundingBox += nsPoint(0, mAscent);
   if (mTextRun->IsVertical()) {
     // Swap line-relative textMetrics dimensions to physical coordinates.
@@ -8375,7 +8467,8 @@ nsTextFrame::ReflowText(nsLineLayout& aLineLayout, nscoord aAvailableWidth,
                                    (GetStateBits() & TEXT_IS_IN_TOKEN_MATHML);
   gfxBreakPriority breakPriority = aLineLayout.LastOptionalBreakPriority();
   gfxTextRun::SuppressBreak suppressBreak = gfxTextRun::eNoSuppressBreak;
-  if (ShouldSuppressLineBreak()) {
+  bool shouldSuppressLineBreak = ShouldSuppressLineBreak();
+  if (shouldSuppressLineBreak) {
     suppressBreak = gfxTextRun::eSuppressAllBreaks;
   } else if (!aLineLayout.LineIsBreakable()) {
     suppressBreak = gfxTextRun::eSuppressInitialBreak;
@@ -8398,6 +8491,10 @@ nsTextFrame::ReflowText(nsLineLayout& aLineLayout, nscoord aAvailableWidth,
       textMetrics.mDescent = gfxFloat(fm->MaxDescent());
     }
   }
+  if (GetWritingMode().IsLineInverted()) {
+    Swap(textMetrics.mAscent, textMetrics.mDescent);
+    textMetrics.mBoundingBox.y = -textMetrics.mBoundingBox.YMost();
+  }
   // The "end" iterator points to the first character after the string mapped
   // by this frame. Basically, its original-string offset is offset+charsFit
   // after we've computed charsFit.
@@ -8503,31 +8600,21 @@ nsTextFrame::ReflowText(nsLineLayout& aLineLayout, nscoord aAvailableWidth,
     finalSize.BSize(wm) = 0;
   } else if (boundingBoxType != gfxFont::LOOSE_INK_EXTENTS) {
     // Use actual text metrics for floating first letter frame.
-    if (wm.IsLineInverted()) {
-      aMetrics.SetBlockStartAscent(NSToCoordCeil(textMetrics.mDescent));
-      finalSize.BSize(wm) = aMetrics.BlockStartAscent() +
-        NSToCoordCeil(textMetrics.mAscent);
-    } else {
-      aMetrics.SetBlockStartAscent(NSToCoordCeil(textMetrics.mAscent));
-      finalSize.BSize(wm) = aMetrics.BlockStartAscent() +
-        NSToCoordCeil(textMetrics.mDescent);
-    }
+    aMetrics.SetBlockStartAscent(NSToCoordCeil(textMetrics.mAscent));
+    finalSize.BSize(wm) = aMetrics.BlockStartAscent() +
+      NSToCoordCeil(textMetrics.mDescent);
   } else {
     // Otherwise, ascent should contain the overline drawable area.
     // And also descent should contain the underline drawable area.
     // nsFontMetrics::GetMaxAscent/GetMaxDescent contains them.
     nsFontMetrics* fm = provider.GetFontMetrics();
-    nscoord fontAscent = fm->MaxAscent();
-    nscoord fontDescent = fm->MaxDescent();
-    if (wm.IsLineInverted()) {
-      aMetrics.SetBlockStartAscent(std::max(NSToCoordCeil(textMetrics.mDescent), fontDescent));
-      nscoord descent = std::max(NSToCoordCeil(textMetrics.mAscent), fontAscent);
-      finalSize.BSize(wm) = aMetrics.BlockStartAscent() + descent;
-    } else {
-      aMetrics.SetBlockStartAscent(std::max(NSToCoordCeil(textMetrics.mAscent), fontAscent));
-      nscoord descent = std::max(NSToCoordCeil(textMetrics.mDescent), fontDescent);
-      finalSize.BSize(wm) = aMetrics.BlockStartAscent() + descent;
-    }
+    nscoord fontAscent =
+      wm.IsLineInverted() ? fm->MaxDescent() : fm->MaxAscent();
+    nscoord fontDescent =
+      wm.IsLineInverted() ? fm->MaxAscent() : fm->MaxDescent();
+    aMetrics.SetBlockStartAscent(std::max(NSToCoordCeil(textMetrics.mAscent), fontAscent));
+    nscoord descent = std::max(NSToCoordCeil(textMetrics.mDescent), fontDescent);
+    finalSize.BSize(wm) = aMetrics.BlockStartAscent() + descent;
   }
   aMetrics.SetSize(wm, finalSize);
 
@@ -8541,14 +8628,18 @@ nsTextFrame::ReflowText(nsLineLayout& aLineLayout, nscoord aAvailableWidth,
 
   // Handle text that runs outside its normal bounds.
   nsRect boundingBox = RoundOut(textMetrics.mBoundingBox);
-  if (wm.IsLineInverted()) {
-    boundingBox.y = -boundingBox.YMost();
-  }
-  boundingBox += nsPoint(0, mAscent);
   if (mTextRun->IsVertical()) {
     // Swap line-relative textMetrics dimensions to physical coordinates.
     Swap(boundingBox.x, boundingBox.y);
     Swap(boundingBox.width, boundingBox.height);
+    if (GetWritingMode().IsVerticalRL()) {
+      boundingBox.x = -boundingBox.XMost();
+      boundingBox.x += aMetrics.Width() - mAscent;
+    } else {
+      boundingBox.x += mAscent;
+    }
+  } else {
+    boundingBox.y += mAscent;
   }
   aMetrics.SetOverflowAreasToDesiredBounds();
   aMetrics.VisualOverflow().UnionRect(aMetrics.VisualOverflow(), boundingBox);
@@ -8572,36 +8663,38 @@ nsTextFrame::ReflowText(nsLineLayout& aLineLayout, nscoord aAvailableWidth,
     aLineLayout.SetTrimmableISize(NSToCoordFloor(trimmableWidth));
     AddStateBits(TEXT_HAS_NONCOLLAPSED_CHARACTERS);
   }
-  if (charsFit > 0 && charsFit == length &&
-      textStyle->mHyphens != NS_STYLE_HYPHENS_NONE &&
-      HasSoftHyphenBefore(frag, mTextRun, offset, end)) {
-    bool fits =
-      textMetrics.mAdvanceWidth + provider.GetHyphenWidth() <= availWidth;
-    // Record a potential break after final soft hyphen
-    aLineLayout.NotifyOptionalBreakPosition(this, length, fits,
-                                            gfxBreakPriority::eNormalBreak);
-  }
   bool breakAfter = forceBreakAfter;
-  // length == 0 means either the text is empty or it's all collapsed away
-  bool emptyTextAtStartOfLine = atStartOfLine && length == 0;
-  if (!breakAfter && charsFit == length && !emptyTextAtStartOfLine &&
-      transformedOffset + transformedLength == mTextRun->GetLength() &&
-      !ShouldSuppressLineBreak() &&
-      (mTextRun->GetFlags() & nsTextFrameUtils::TEXT_HAS_TRAILING_BREAK)) {
-    // We placed all the text in the textrun and we have a break opportunity at
-    // the end of the textrun. We need to record it because the following
-    // content may not care about nsLineBreaker.
-
-    // Note that because we didn't break, we can be sure that (thanks to the
-    // code up above) textMetrics.mAdvanceWidth includes the width of any
-    // trailing whitespace. So we need to subtract trimmableWidth here
-    // because if we did break at this point, that much width would be trimmed.
-    if (textMetrics.mAdvanceWidth - trimmableWidth > availWidth) {
-      breakAfter = true;
-    } else {
-      aLineLayout.NotifyOptionalBreakPosition(this, length, true,
+  if (!shouldSuppressLineBreak) {
+    if (charsFit > 0 && charsFit == length &&
+        textStyle->mHyphens != NS_STYLE_HYPHENS_NONE &&
+        HasSoftHyphenBefore(frag, mTextRun, offset, end)) {
+      bool fits =
+        textMetrics.mAdvanceWidth + provider.GetHyphenWidth() <= availWidth;
+      // Record a potential break after final soft hyphen
+      aLineLayout.NotifyOptionalBreakPosition(this, length, fits,
                                               gfxBreakPriority::eNormalBreak);
     }
+    // length == 0 means either the text is empty or it's all collapsed away
+    bool emptyTextAtStartOfLine = atStartOfLine && length == 0;
+    if (!breakAfter && charsFit == length && !emptyTextAtStartOfLine &&
+        transformedOffset + transformedLength == mTextRun->GetLength() &&
+        (mTextRun->GetFlags() & nsTextFrameUtils::TEXT_HAS_TRAILING_BREAK)) {
+      // We placed all the text in the textrun and we have a break opportunity
+      // at the end of the textrun. We need to record it because the following
+      // content may not care about nsLineBreaker.
+
+      // Note that because we didn't break, we can be sure that (thanks to the
+      // code up above) textMetrics.mAdvanceWidth includes the width of any
+      // trailing whitespace. So we need to subtract trimmableWidth here
+      // because if we did break at this point, that much width would be
+      // trimmed.
+      if (textMetrics.mAdvanceWidth - trimmableWidth > availWidth) {
+        breakAfter = true;
+      } else {
+        aLineLayout.NotifyOptionalBreakPosition(this, length, true,
+                                                gfxBreakPriority::eNormalBreak);
+      }
+    }
   }
 
   // Compute reflow status
@@ -8650,7 +8743,7 @@ nsTextFrame::ReflowText(nsLineLayout& aLineLayout, nscoord aAvailableWidth,
   if (!textStyle->WhiteSpaceIsSignificant() &&
       (lineContainer->StyleText()->mTextAlign == NS_STYLE_TEXT_ALIGN_JUSTIFY ||
        lineContainer->StyleText()->mTextAlignLast == NS_STYLE_TEXT_ALIGN_JUSTIFY ||
-       ShouldSuppressLineBreak()) &&
+       shouldSuppressLineBreak) &&
       !lineContainer->IsSVGText()) {
     AddStateBits(TEXT_JUSTIFICATION_ENABLED);
     provider.ComputeJustification(offset, charsFit);
@@ -8754,7 +8847,7 @@ nsTextFrame::TrimTrailingWhiteSpace(nsRenderingContext* aRC)
 }
 
 nsOverflowAreas
-nsTextFrame::RecomputeOverflow(const nsHTMLReflowState& aBlockReflowState)
+nsTextFrame::RecomputeOverflow(nsIFrame* aBlockFrame)
 {
   nsRect bounds(nsPoint(0, 0), GetSize());
   nsOverflowAreas result(bounds, bounds);
@@ -8772,10 +8865,10 @@ nsTextFrame::RecomputeOverflow(const nsHTMLReflowState& aBlockReflowState)
                           ComputeTransformedLength(provider),
                           gfxFont::LOOSE_INK_EXTENTS, nullptr,
                           &provider);
-  nsRect boundingBox = RoundOut(textMetrics.mBoundingBox);
   if (GetWritingMode().IsLineInverted()) {
-    boundingBox.y = -boundingBox.YMost();
+    textMetrics.mBoundingBox.y = -textMetrics.mBoundingBox.YMost();
   }
+  nsRect boundingBox = RoundOut(textMetrics.mBoundingBox);
   boundingBox += nsPoint(0, mAscent);
   if (mTextRun->IsVertical()) {
     // Swap line-relative textMetrics dimensions to physical coordinates.
@@ -8784,8 +8877,7 @@ nsTextFrame::RecomputeOverflow(const nsHTMLReflowState& aBlockReflowState)
   }
   nsRect &vis = result.VisualOverflow();
   vis.UnionRect(vis, boundingBox);
-  UnionAdditionalOverflow(PresContext(), aBlockReflowState.frame, provider,
-                          &vis, true);
+  UnionAdditionalOverflow(PresContext(), aBlockFrame, provider, &vis, true);
   return result;
 }
 
@@ -9159,18 +9251,9 @@ nsTextFrame::HasAnyNoncollapsedCharacters()
 bool
 nsTextFrame::UpdateOverflow()
 {
-  const nsRect rect(nsPoint(0, 0), GetSize());
-  nsOverflowAreas overflowAreas(rect, rect);
-
   if (GetStateBits() & NS_FRAME_FIRST_REFLOW) {
     return false;
   }
-  gfxSkipCharsIterator iter = EnsureTextRun(nsTextFrame::eInflated);
-  if (!mTextRun) {
-    return false;
-  }
-  PropertyProvider provider(this, iter, nsTextFrame::eInflated);
-  provider.InitializeForDisplay(true);
 
   nsIFrame* decorationsBlock;
   if (IsFloatingFirstLetterChild()) {
@@ -9192,8 +9275,8 @@ nsTextFrame::UpdateOverflow()
     }
   }
 
-  UnionAdditionalOverflow(PresContext(), decorationsBlock, provider,
-                          &overflowAreas.VisualOverflow(), true);
+  nsOverflowAreas overflowAreas = RecomputeOverflow(decorationsBlock);
+
   return FinishAndStoreOverflow(overflowAreas, GetSize());
 }
 
diff --git a/layout/generic/nsTextFrame.h b/layout/generic/nsTextFrame.h
index 2297d09b63..0a2ff356b2 100644
--- a/layout/generic/nsTextFrame.h
+++ b/layout/generic/nsTextFrame.h
@@ -7,6 +7,7 @@
 #define nsTextFrame_h__
 
 #include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
 #include "mozilla/gfx/2D.h"
 #include "nsFrame.h"
 #include "nsGenericDOMDataNode.h"
@@ -40,6 +41,7 @@ public:
 };
 
 class nsTextFrame : public nsTextFrameBase {
+  typedef mozilla::TextRangeStyle TextRangeStyle;
   typedef mozilla::gfx::DrawTarget DrawTarget;
   typedef mozilla::gfx::Rect Rect;
 
@@ -281,8 +283,7 @@ public:
                                        TextOffsetType aOffsetType =
                                            TextOffsetType::OFFSETS_IN_CONTENT_TEXT) override;
 
-  nsOverflowAreas
-    RecomputeOverflow(const nsHTMLReflowState& aBlockReflowState);
+  nsOverflowAreas RecomputeOverflow(nsIFrame* aBlockFrame);
 
   enum TextRunType {
     // Anything in reflow (but not intrinsic width calculation) or
@@ -745,6 +746,74 @@ protected:
   bool CombineSelectionUnderlineRect(nsPresContext* aPresContext,
                                        nsRect& aRect);
 
+  /**
+   * Utility methods to paint selection.
+   */
+  void DrawSelectionDecorations(gfxContext* aContext,
+                                const gfxRect& aDirtyRect,
+                                SelectionType aType,
+                                nsTextPaintStyle& aTextPaintStyle,
+                                const TextRangeStyle &aRangeStyle,
+                                const gfxPoint& aPt,
+                                gfxFloat aICoordInFrame,
+                                gfxFloat aWidth,
+                                gfxFloat aAscent,
+                                const gfxFont::Metrics& aFontMetrics,
+                                DrawPathCallbacks* aCallbacks,
+                                bool aVertical,
+                                uint8_t aDecoration);
+  enum DecorationType
+  {
+    eNormalDecoration,
+    eSelectionDecoration
+  };
+  void PaintDecorationLine(gfxContext* const aCtx,
+                           const gfxRect& aDirtyRect,
+                           nscolor aColor,
+                           const nscolor* aOverrideColor,
+                           const gfxPoint& aPt,
+                           gfxFloat aICoordInFrame,
+                           const gfxSize& aLineSize,
+                           gfxFloat aAscent,
+                           gfxFloat aOffset,
+                           uint8_t aDecoration,
+                           uint8_t aStyle,
+                           DecorationType aDecorationType,
+                           DrawPathCallbacks* aCallbacks,
+                           bool aVertical,
+                           gfxFloat aDescentLimit = -1.0);
+  /**
+   * ComputeDescentLimitForSelectionUnderline() computes the most far position
+   * where we can put selection underline.
+   *
+   * @return The maximum underline offset from the baseline (positive value
+   *         means that the underline can put below the baseline).
+   */
+  gfxFloat ComputeDescentLimitForSelectionUnderline(
+             nsPresContext* aPresContext,
+             const gfxFont::Metrics& aFontMetrics);
+  /**
+   * This function encapsulates all knowledge of how selections affect
+   * foreground and background colors.
+   * @param aForeground the foreground color to use
+   * @param aBackground the background color to use, or RGBA(0,0,0,0) if no
+   *                    background should be painted
+   * @return            true if the selection affects colors, false otherwise
+   */
+  static bool GetSelectionTextColors(SelectionType aType,
+                                     nsTextPaintStyle& aTextPaintStyle,
+                                     const TextRangeStyle &aRangeStyle,
+                                     nscolor* aForeground,
+                                     nscolor* aBackground);
+  /**
+   * ComputeSelectionUnderlineHeight() computes selection underline height of
+   * the specified selection type from the font metrics.
+   */
+  static gfxFloat ComputeSelectionUnderlineHeight(
+                    nsPresContext* aPresContext,
+                    const gfxFont::Metrics& aFontMetrics,
+                    SelectionType aSelectionType);
+
   ContentOffsets GetCharacterOffsetAtFramePointInternal(nsPoint aPoint,
                    bool aForInsertionPoint);
 
diff --git a/layout/reftests/css-ruby/line-break-suppression-5-ref.html b/layout/reftests/css-ruby/line-break-suppression-5-ref.html
new file mode 100644
index 0000000000..d646dba0c4
--- /dev/null
+++ b/layout/reftests/css-ruby/line-break-suppression-5-ref.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <title>Bug 1186720 - Line break suppression with soft hyphen</title>
+</head>
+<body style="width: 1px">
+  x<ruby>a</ruby>
+</body>
+</html>
diff --git a/layout/reftests/css-ruby/line-break-suppression-5.html b/layout/reftests/css-ruby/line-break-suppression-5.html
new file mode 100644
index 0000000000..a44856c8d0
--- /dev/null
+++ b/layout/reftests/css-ruby/line-break-suppression-5.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <title>Bug 1186720 - Line break suppression with soft hyphen</title>
+</head>
+<body style="width: 1px">
+  x<ruby>a&shy;</ruby>
+</body>
+</html>
diff --git a/layout/reftests/css-ruby/reftest.list b/layout/reftests/css-ruby/reftest.list
index 18091598f9..9ab3f19c98 100644
--- a/layout/reftests/css-ruby/reftest.list
+++ b/layout/reftests/css-ruby/reftest.list
@@ -30,6 +30,7 @@ test-pref(dom.meta-viewport.enabled,true) test-pref(font.size.inflation.emPerLin
 == line-break-suppression-2.html line-break-suppression-2-ref.html
 == line-break-suppression-3.html line-break-suppression-3-ref.html
 == line-break-suppression-4.html line-break-suppression-4-ref.html
+== line-break-suppression-5.html line-break-suppression-5-ref.html
 == line-height-1.html line-height-1-ref.html
 == line-height-2.html line-height-2-ref.html
 == line-height-3.html line-height-3-ref.html
diff --git a/layout/reftests/w3c-css/submitted/text-decor-3/reftest.list b/layout/reftests/w3c-css/submitted/text-decor-3/reftest.list
index bf1b104b47..5218255fbc 100644
--- a/layout/reftests/w3c-css/submitted/text-decor-3/reftest.list
+++ b/layout/reftests/w3c-css/submitted/text-decor-3/reftest.list
@@ -1 +1,2 @@
 pref(layout.css.ruby.enabled,true) == ruby-text-decoration-01.html ruby-text-decoration-01-ref.html
+== text-decoration-propagation-01.html text-decoration-propagation-01-ref.html
diff --git a/layout/reftests/w3c-css/submitted/text-decor-3/text-decoration-propagation-01-ref.html b/layout/reftests/w3c-css/submitted/text-decor-3/text-decoration-propagation-01-ref.html
new file mode 100644
index 0000000000..fe5b2191c9
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text-decor-3/text-decoration-propagation-01-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Cameron McCormack" href="mailto:cam@mcc.id.au">
+<span>
+  <svg width="400" height="100">
+    <text x="10" y="30">This text must not be underlined.</text>
+  </svg>
+</span>
diff --git a/layout/reftests/w3c-css/submitted/text-decor-3/text-decoration-propagation-01.html b/layout/reftests/w3c-css/submitted/text-decor-3/text-decoration-propagation-01.html
new file mode 100644
index 0000000000..45e680d4d0
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text-decor-3/text-decoration-propagation-01.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: text-decoration shouldn't propagate through 'svg' element</title>
+<link rel="author" title="Cameron McCormack" href="mailto:cam@mcc.id.au">
+<link rel="help" href="http://www.w3.org/TR/css-text-decor-3/#line-decoration">
+<link rel="match" href="text-decoration-propagation-01-ref.html">
+<meta name="assert" content="An outer 'svg' element is an atomic inline-axis element, so text decorations must not propagate through it.">
+<style>
+span { text-decoration: underline; }
+</style>
+<span>
+  <svg width="400" height="100">
+    <text x="10" y="30">This text must not be underlined.</text>
+  </svg>
+</span>
diff --git a/layout/reftests/writing-mode/1175789-underline-overline-1-ref.html b/layout/reftests/writing-mode/1175789-underline-overline-1-ref.html
new file mode 100644
index 0000000000..b788d6bae8
--- /dev/null
+++ b/layout/reftests/writing-mode/1175789-underline-overline-1-ref.html
@@ -0,0 +1,91 @@
+<!DOCTYPE html>
+<html>
+ <head>
+  <title>Bug 1175789 - underline and overline in various language</title>
+  <style type="text/css">
+    body {
+      font-family: "Arial", "Helvetica", "sans-serif";
+    }
+    div {
+      padding: .5em 1em;
+      line-height: 2em;
+    }
+    .underline {
+      text-decoration: underline;
+    }
+    .overline {
+      text-decoration: overline;
+    }
+  </style>
+ </head>
+ <body>
+   <dl>
+     <dt>lang="en-US"</dt>
+     <dd lang="en-US">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ja"</dt>
+     <dd lang="en-US">
+       <div style="writing-mode: vertical-rl;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ko"</dt>
+     <dd lang="en-US">
+       <div style="writing-mode: vertical-rl;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ja-JP"</dt>
+     <dd lang="en-US">
+       <div style="writing-mode: vertical-rl;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ko-KR"</dt>
+     <dd lang="en-US">
+       <div style="writing-mode: vertical-rl;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="overline">underline</span><br>
+         <span class="underline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="zh"</dt>
+     <dd lang="en-US">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+    </dl>
+ </body>
+</html>
diff --git a/layout/reftests/writing-mode/1175789-underline-overline-1.html b/layout/reftests/writing-mode/1175789-underline-overline-1.html
new file mode 100644
index 0000000000..1044a9dca5
--- /dev/null
+++ b/layout/reftests/writing-mode/1175789-underline-overline-1.html
@@ -0,0 +1,91 @@
+<!DOCTYPE html>
+<html>
+ <head>
+  <title>Bug 1175789 - underline and overline in various language</title>
+  <style type="text/css">
+    body {
+      font-family: "Arial", "Helvetica", "sans-serif";
+    }
+    div {
+      padding: .5em 1em;
+      line-height: 2em;
+    }
+    .underline {
+      text-decoration: underline;
+    }
+    .overline {
+      text-decoration: overline;
+    }
+  </style>
+ </head>
+ <body>
+   <dl>
+     <dt>lang="en-US"</dt>
+     <dd lang="en-US">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ja"</dt>
+     <dd lang="ja">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ko"</dt>
+     <dd lang="ko">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ja-JP"</dt>
+     <dd lang="ja-JP">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="ko-KR"</dt>
+     <dd lang="ko-KR">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+     <dt>lang="zh"</dt>
+     <dd lang="zh">
+       <div style="writing-mode: vertical-rl;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+       <div style="writing-mode: vertical-lr;">
+         <span class="underline">underline</span><br>
+         <span class="overline">overline</span>
+       </div>
+     </dd>
+    </dl>
+ </body>
+</html>
diff --git a/layout/reftests/writing-mode/reftest.list b/layout/reftests/writing-mode/reftest.list
index 4fe9f36564..86c600c353 100644
--- a/layout/reftests/writing-mode/reftest.list
+++ b/layout/reftests/writing-mode/reftest.list
@@ -149,6 +149,7 @@ test-pref(dom.meta-viewport.enabled,true) test-pref(font.size.inflation.emPerLin
 == 1172774-percent-padding-3.html 1172774-percent-vertical-ref.html
 == 1172774-percent-padding-4.html 1172774-percent-vertical-ref.html
 == 1174450-intrinsic-sizing.html 1174450-intrinsic-sizing-ref.html
+== 1175789-underline-overline-1.html 1175789-underline-overline-1-ref.html
 
 # Suite of tests from Gérard Talbot in bug 1079151
 include abspos/reftest.list
diff --git a/widget/ContentCache.cpp b/widget/ContentCache.cpp
index 2e6bac9af2..3ea10e8b7b 100644
--- a/widget/ContentCache.cpp
+++ b/widget/ContentCache.cpp
@@ -39,8 +39,8 @@ GetEventMessageName(EventMessage aMessage)
       return "NS_COMPOSITION_COMMIT_AS_IS";
     case NS_COMPOSITION_COMMIT:
       return "NS_COMPOSITION_COMMIT";
-    case NS_SELECTION_SET:
-      return "NS_SELECTION_SET";
+    case eSetSelection:
+      return "eSetSelection";
     default:
       return "unacceptable event message";
   }
@@ -177,7 +177,7 @@ ContentCacheInChild::CacheSelection(nsIWidget* aWidget,
   mSelection.Clear();
 
   nsEventStatus status = nsEventStatus_eIgnore;
-  WidgetQueryContentEvent selection(true, NS_QUERY_SELECTED_TEXT, aWidget);
+  WidgetQueryContentEvent selection(true, eQuerySelectedText, aWidget);
   aWidget->DispatchEvent(&selection, status);
   if (NS_WARN_IF(!selection.mSucceeded)) {
     MOZ_LOG(sContentCacheLog, LogLevel::Error,
@@ -219,7 +219,7 @@ ContentCacheInChild::CacheCaret(nsIWidget* aWidget,
   mCaret.mOffset = mSelection.StartOffset();
 
   nsEventStatus status = nsEventStatus_eIgnore;
-  WidgetQueryContentEvent caretRect(true, NS_QUERY_CARET_RECT, aWidget);
+  WidgetQueryContentEvent caretRect(true, eQueryCaretRect, aWidget);
   caretRect.InitForQueryCaretRect(mCaret.mOffset);
   aWidget->DispatchEvent(&caretRect, status);
   if (NS_WARN_IF(!caretRect.mSucceeded)) {
@@ -276,7 +276,7 @@ ContentCacheInChild::CacheText(nsIWidget* aWidget,
      this, aWidget, GetNotificationName(aNotification)));
 
   nsEventStatus status = nsEventStatus_eIgnore;
-  WidgetQueryContentEvent queryText(true, NS_QUERY_TEXT_CONTENT, aWidget);
+  WidgetQueryContentEvent queryText(true, eQueryTextContent, aWidget);
   queryText.InitForQueryTextContent(0, UINT32_MAX);
   aWidget->DispatchEvent(&queryText, status);
   if (NS_WARN_IF(!queryText.mSucceeded)) {
@@ -516,10 +516,10 @@ ContentCacheInParent::HandleQueryContentEvent(WidgetQueryContentEvent& aEvent,
   aEvent.mReply.mFocusedWidget = aWidget;
 
   switch (aEvent.mMessage) {
-    case NS_QUERY_SELECTED_TEXT:
+    case eQuerySelectedText:
       MOZ_LOG(sContentCacheLog, LogLevel::Info,
         ("ContentCacheInParent: 0x%p HandleQueryContentEvent("
-         "aEvent={ mMessage=NS_QUERY_SELECTED_TEXT }, aWidget=0x%p)",
+         "aEvent={ mMessage=eQuerySelectedText }, aWidget=0x%p)",
          this, aWidget));
       if (NS_WARN_IF(!IsSelectionValid())) {
         // If content cache hasn't been initialized properly, make the query
@@ -557,10 +557,10 @@ ContentCacheInParent::HandleQueryContentEvent(WidgetQueryContentEvent& aEvent,
          GetBoolName(aEvent.mReply.mHasSelection),
          GetWritingModeName(aEvent.mReply.mWritingMode).get()));
       break;
-    case NS_QUERY_TEXT_CONTENT: {
+    case eQueryTextContent: {
       MOZ_LOG(sContentCacheLog, LogLevel::Info,
         ("ContentCacheInParent: 0x%p HandleQueryContentEvent("
-         "aEvent={ mMessage=NS_QUERY_TEXT_CONTENT, mInput={ mOffset=%u, "
+         "aEvent={ mMessage=eQueryTextContent, mInput={ mOffset=%u, "
          "mLength=%u } }, aWidget=0x%p), mText.Length()=%u",
          this, aEvent.mInput.mOffset,
          aEvent.mInput.mLength, aWidget, mText.Length()));
@@ -638,10 +638,10 @@ ContentCacheInParent::HandleQueryContentEvent(WidgetQueryContentEvent& aEvent,
          GetWritingModeName(aEvent.mReply.mWritingMode).get(),
          GetRectText(aEvent.mReply.mRect).get()));
       break;
-    case NS_QUERY_CARET_RECT:
+    case eQueryCaretRect:
       MOZ_LOG(sContentCacheLog, LogLevel::Info,
         ("ContentCacheInParent: 0x%p HandleQueryContentEvent("
-         "aEvent={ mMessage=NS_QUERY_CARET_RECT, mInput={ mOffset=%u } }, "
+         "aEvent={ mMessage=eQueryCaretRect, mInput={ mOffset=%u } }, "
          "aWidget=0x%p), mText.Length()=%u",
          this, aEvent.mInput.mOffset, aWidget, mText.Length()));
       if (NS_WARN_IF(!IsSelectionValid())) {
diff --git a/widget/ContentCache.h b/widget/ContentCache.h
index 955964b56c..79367ac718 100644
--- a/widget/ContentCache.h
+++ b/widget/ContentCache.h
@@ -282,13 +282,13 @@ public:
   /**
    * HandleQueryContentEvent() sets content data to aEvent.mReply.
    *
-   * For NS_QUERY_SELECTED_TEXT, fail if the cache doesn't contain the whole
+   * For eQuerySelectedText, fail if the cache doesn't contain the whole
    *  selected range. (This shouldn't happen because PuppetWidget should have
    *  already sent the whole selection.)
    *
-   * For NS_QUERY_TEXT_CONTENT, fail only if the cache doesn't overlap with
+   * For eQueryTextContent, fail only if the cache doesn't overlap with
    *  the queried range. Note the difference from above. We use
-   *  this behavior because a normal NS_QUERY_TEXT_CONTENT event is allowed to
+   *  this behavior because a normal eQueryTextContent event is allowed to
    *  have out-of-bounds offsets, so that widget can request content without
    *  knowing the exact length of text. It's up to widget to handle cases when
    *  the returned offset/length are different from the queried offset/length.
@@ -296,7 +296,7 @@ public:
    * For NS_QUERY_TEXT_RECT, fail if cached offset/length aren't equals to input.
    *   Cocoa widget always queries selected offset, so it works on it.
    *
-   * For NS_QUERY_CARET_RECT, fail if cached offset isn't equals to input
+   * For eQueryCaretRect, fail if cached offset isn't equals to input
    *
    * For NS_QUERY_EDITOR_RECT, always success
    */
diff --git a/widget/EventMessageList.h b/widget/EventMessageList.h
index 5c11981f92..4900298a90 100644
--- a/widget/EventMessageList.h
+++ b/widget/EventMessageList.h
@@ -123,10 +123,10 @@ NS_EVENT_MESSAGE(eXULPopupHidden,       eXULEventFirst + 3)
 NS_EVENT_MESSAGE(eXULBroadcast,         eXULEventFirst + 5)
 NS_EVENT_MESSAGE(eXULCommandUpdate,     eXULEventFirst + 6)
 
-// Scroll events
-NS_EVENT_MESSAGE(NS_MOUSE_SCROLL_START, 1600)
-NS_EVENT_MESSAGE(NS_MOUSE_SCROLL,       NS_MOUSE_SCROLL_START)
-NS_EVENT_MESSAGE(NS_MOUSE_PIXEL_SCROLL, NS_MOUSE_SCROLL_START + 1)
+// Legacy mouse scroll (wheel) events
+NS_EVENT_MESSAGE(eLegacyMouseScrollEventFirst, 1600)
+NS_EVENT_MESSAGE(eLegacyMouseLineOrPageScroll, eLegacyMouseScrollEventFirst)
+NS_EVENT_MESSAGE(eLegacyMousePixelScroll,      eLegacyMouseScrollEventFirst + 1)
 
 NS_EVENT_MESSAGE(NS_SCROLLPORT_START,     1700)
 NS_EVENT_MESSAGE(NS_SCROLLPORT_UNDERFLOW, NS_SCROLLPORT_START)
@@ -212,36 +212,36 @@ NS_EVENT_MESSAGE(eCut,                  eClipboardEventFirst + 1)
 NS_EVENT_MESSAGE(ePaste,                eClipboardEventFirst + 2)
 
 // Query the content information
-NS_EVENT_MESSAGE(NS_QUERY_CONTENT_EVENT_START,       3200)
+NS_EVENT_MESSAGE(eQueryContentEventFirst,       3200)
 // Query for the selected text information, it return the selection offset,
 // selection length and selected text.
-NS_EVENT_MESSAGE(NS_QUERY_SELECTED_TEXT,             NS_QUERY_CONTENT_EVENT_START)
+NS_EVENT_MESSAGE(eQuerySelectedText,            eQueryContentEventFirst)
 // Query for the text content of specified range, it returns actual lengh (if
 // the specified range is too long) and the text of the specified range.
 // Returns the entire text if requested length > actual length.
-NS_EVENT_MESSAGE(NS_QUERY_TEXT_CONTENT,              NS_QUERY_CONTENT_EVENT_START + 1)
+NS_EVENT_MESSAGE(eQueryTextContent,             eQueryContentEventFirst + 1)
 // Query for the caret rect of nth insertion point. The offset of the result is
 // relative position from the top level widget.
-NS_EVENT_MESSAGE(NS_QUERY_CARET_RECT,                NS_QUERY_CONTENT_EVENT_START + 3)
+NS_EVENT_MESSAGE(eQueryCaretRect,               eQueryContentEventFirst + 3)
 // Query for the bounding rect of a range of characters. This works on any
 // valid character range given offset and length. Result is relative to top
 // level widget coordinates
-NS_EVENT_MESSAGE(NS_QUERY_TEXT_RECT,                 NS_QUERY_CONTENT_EVENT_START + 4)
+NS_EVENT_MESSAGE(NS_QUERY_TEXT_RECT,            eQueryContentEventFirst + 4)
 // Query for the bounding rect of the current focused frame. Result is relative
 // to top level widget coordinates
-NS_EVENT_MESSAGE(NS_QUERY_EDITOR_RECT,               NS_QUERY_CONTENT_EVENT_START + 5)
+NS_EVENT_MESSAGE(NS_QUERY_EDITOR_RECT,          eQueryContentEventFirst + 5)
 // Query for the current state of the content. The particular members of
 // mReply that are set for each query content event will be valid on success.
-NS_EVENT_MESSAGE(NS_QUERY_CONTENT_STATE,             NS_QUERY_CONTENT_EVENT_START + 6)
+NS_EVENT_MESSAGE(NS_QUERY_CONTENT_STATE,        eQueryContentEventFirst + 6)
 // Query for the selection in the form of a nsITransferable.
-NS_EVENT_MESSAGE(NS_QUERY_SELECTION_AS_TRANSFERABLE, NS_QUERY_CONTENT_EVENT_START + 7)
+NS_EVENT_MESSAGE(eQuerySelectionAsTransferable, eQueryContentEventFirst + 7)
 // Query for character at a point.  This returns the character offset, its
 // rect and also tentative caret point if the point is clicked.  The point is
 // specified by Event::refPoint.
-NS_EVENT_MESSAGE(NS_QUERY_CHARACTER_AT_POINT,        NS_QUERY_CONTENT_EVENT_START + 8)
+NS_EVENT_MESSAGE(NS_QUERY_CHARACTER_AT_POINT,   eQueryContentEventFirst + 8)
 // Query if the DOM element under Event::refPoint belongs to our widget
 // or not.
-NS_EVENT_MESSAGE(NS_QUERY_DOM_WIDGET_HITTEST,        NS_QUERY_CONTENT_EVENT_START + 9)
+NS_EVENT_MESSAGE(NS_QUERY_DOM_WIDGET_HITTEST,   eQueryContentEventFirst + 9)
 
 // Video events
 NS_EVENT_MESSAGE(eMediaEventFirst,      3300)
@@ -295,7 +295,7 @@ NS_EVENT_MESSAGE(ePluginInputEvent,     ePluginEventFirst)
 // Events to manipulate selection (WidgetSelectionEvent)
 NS_EVENT_MESSAGE(eSelectionEventFirst,  3700)
 // Clear any previous selection and set the given range as the selection
-NS_EVENT_MESSAGE(NS_SELECTION_SET,      eSelectionEventFirst)
+NS_EVENT_MESSAGE(eSetSelection,         eSelectionEventFirst)
 
 // Events of commands for the contents
 NS_EVENT_MESSAGE(NS_CONTENT_COMMAND_EVENT_START,        3800)
diff --git a/widget/MouseEvents.h b/widget/MouseEvents.h
index 8961b15179..cd706d7ce5 100644
--- a/widget/MouseEvents.h
+++ b/widget/MouseEvents.h
@@ -399,11 +399,11 @@ public:
   }
 
   // The delta value of mouse scroll event.
-  // If the event message is NS_MOUSE_SCROLL, the value indicates scroll amount
-  // in lines.  However, if the value is nsIDOMUIEvent::SCROLL_PAGE_UP or
-  // nsIDOMUIEvent::SCROLL_PAGE_DOWN, the value inducates one page scroll.
-  // If the event message is NS_MOUSE_PIXEL_SCROLL, the value indicates scroll
-  // amount in pixels.
+  // If the event message is eLegacyMouseLineOrPageScroll, the value indicates
+  // scroll amount in lines.  However, if the value is
+  // nsIDOMUIEvent::SCROLL_PAGE_UP or nsIDOMUIEvent::SCROLL_PAGE_DOWN, the
+  // value inducates one page scroll.  If the event message is
+  // eLegacyMousePixelScroll, the value indicates scroll amount in pixels.
   int32_t delta;
 
   // If this is true, it may cause to scroll horizontally.
@@ -499,13 +499,14 @@ public:
 
   // If device event handlers don't know when they should set lineOrPageDeltaX
   // and lineOrPageDeltaY, this is true.  Otherwise, false.
-  // If mIsNoLineOrPageDelta is true, ESM will generate NS_MOUSE_SCROLL events
-  // when accumulated delta values reach a line height.
+  // If mIsNoLineOrPageDelta is true, ESM will generate
+  // eLegacyMouseLineOrPageScroll events when accumulated delta values reach
+  // a line height.
   bool mIsNoLineOrPageDelta;
 
   // If widget sets lineOrPageDelta, EventStateManager will dispatch
-  // NS_MOUSE_SCROLL event for compatibility.  Note that the delta value means
-  // pages if the deltaMode is DOM_DELTA_PAGE, otherwise, lines.
+  // eLegacyMouseLineOrPageScroll event for compatibility.  Note that the delta
+  // value means pages if the deltaMode is DOM_DELTA_PAGE, otherwise, lines.
   int32_t lineOrPageDeltaX;
   int32_t lineOrPageDeltaY;
 
diff --git a/widget/TextEvents.h b/widget/TextEvents.h
index f24dbc1dc8..75c5588616 100644
--- a/widget/TextEvents.h
+++ b/widget/TextEvents.h
@@ -495,7 +495,7 @@ public:
   void InitForQueryTextContent(uint32_t aOffset, uint32_t aLength,
                                bool aUseNativeLineBreak = true)
   {
-    NS_ASSERTION(mMessage == NS_QUERY_TEXT_CONTENT,
+    NS_ASSERTION(mMessage == eQueryTextContent,
                  "wrong initializer is called");
     mInput.mOffset = aOffset;
     mInput.mLength = aLength;
@@ -505,7 +505,7 @@ public:
   void InitForQueryCaretRect(uint32_t aOffset,
                              bool aUseNativeLineBreak = true)
   {
-    NS_ASSERTION(mMessage == NS_QUERY_CARET_RECT,
+    NS_ASSERTION(mMessage == eQueryCaretRect,
                  "wrong initializer is called");
     mInput.mOffset = aOffset;
     mUseNativeLineBreak = aUseNativeLineBreak;
@@ -530,29 +530,29 @@ public:
 
   void RequestFontRanges()
   {
-    NS_ASSERTION(mMessage == NS_QUERY_TEXT_CONTENT,
+    NS_ASSERTION(mMessage == eQueryTextContent,
                  "not querying text content");
     mWithFontRanges = true;
   }
 
   uint32_t GetSelectionStart(void) const
   {
-    NS_ASSERTION(mMessage == NS_QUERY_SELECTED_TEXT,
+    NS_ASSERTION(mMessage == eQuerySelectedText,
                  "not querying selection");
     return mReply.mOffset + (mReply.mReversed ? mReply.mString.Length() : 0);
   }
 
   uint32_t GetSelectionEnd(void) const
   {
-    NS_ASSERTION(mMessage == NS_QUERY_SELECTED_TEXT,
+    NS_ASSERTION(mMessage == eQuerySelectedText,
                  "not querying selection");
     return mReply.mOffset + (mReply.mReversed ? 0 : mReply.mString.Length());
   }
 
   mozilla::WritingMode GetWritingMode(void) const
   {
-    NS_ASSERTION(mMessage == NS_QUERY_SELECTED_TEXT ||
-                 mMessage == NS_QUERY_CARET_RECT ||
+    NS_ASSERTION(mMessage == eQuerySelectedText ||
+                 mMessage == eQueryCaretRect ||
                  mMessage == NS_QUERY_TEXT_RECT,
                  "not querying selection or text rect");
     return mReply.mWritingMode;
@@ -593,9 +593,9 @@ public:
     bool mWidgetIsHit;
     // mozilla::WritingMode value at the end (focus) of the selection
     mozilla::WritingMode mWritingMode;
-    // used by NS_QUERY_SELECTION_AS_TRANSFERABLE
+    // Used by eQuerySelectionAsTransferable
     nsCOMPtr<nsITransferable> mTransferable;
-    // used by NS_QUERY_TEXT_CONTENT with font ranges requested
+    // Used by eQueryTextContent with font ranges requested
     nsAutoTArray<mozilla::FontRange, 1> mFontRanges;
   } mReply;
 
diff --git a/widget/cocoa/TextInputHandler.h b/widget/cocoa/TextInputHandler.h
index fa554309a2..ce297ba701 100644
--- a/widget/cocoa/TextInputHandler.h
+++ b/widget/cocoa/TextInputHandler.h
@@ -356,7 +356,7 @@ public:
   bool DispatchEvent(WidgetGUIEvent& aEvent);
 
   /**
-   * SetSelection() dispatches NS_SELECTION_SET event for the aRange.
+   * SetSelection() dispatches eSetSelection event for the aRange.
    *
    * @param aRange                The range which will be selected.
    * @return                      TRUE if setting selection is succeeded and
diff --git a/widget/cocoa/TextInputHandler.mm b/widget/cocoa/TextInputHandler.mm
index 6784d865c8..34e76608f5 100644
--- a/widget/cocoa/TextInputHandler.mm
+++ b/widget/cocoa/TextInputHandler.mm
@@ -2969,7 +2969,7 @@ IMEInputHandler::ConversationIdentifier()
   nsRefPtr<IMEInputHandler> kungFuDeathGrip(this);
 
   // NOTE: The size of NSInteger is same as pointer size.
-  WidgetQueryContentEvent textContent(true, NS_QUERY_TEXT_CONTENT, mWidget);
+  WidgetQueryContentEvent textContent(true, eQueryTextContent, mWidget);
   textContent.InitForQueryTextContent(0, 0);
   DispatchEvent(textContent);
   if (!textContent.mSucceeded) {
@@ -3005,7 +3005,7 @@ IMEInputHandler::GetAttributedSubstringFromRange(NSRange& aRange,
   nsRefPtr<IMEInputHandler> kungFuDeathGrip(this);
 
   nsAutoString str;
-  WidgetQueryContentEvent textContent(true, NS_QUERY_TEXT_CONTENT, mWidget);
+  WidgetQueryContentEvent textContent(true, eQueryTextContent, mWidget);
   textContent.InitForQueryTextContent(aRange.location, aRange.length);
   textContent.RequestFontRanges();
   DispatchEvent(textContent);
@@ -3098,7 +3098,7 @@ IMEInputHandler::SelectedRange()
 
   nsRefPtr<IMEInputHandler> kungFuDeathGrip(this);
 
-  WidgetQueryContentEvent selection(true, NS_QUERY_SELECTED_TEXT, mWidget);
+  WidgetQueryContentEvent selection(true, eQuerySelectedText, mWidget);
   DispatchEvent(selection);
 
   MOZ_LOG(gLog, LogLevel::Info,
@@ -3202,7 +3202,7 @@ IMEInputHandler::FirstRectForCharacterRange(NSRange& aRange,
   }
 
   if (useCaretRect) {
-    WidgetQueryContentEvent caretRect(true, NS_QUERY_CARET_RECT, mWidget);
+    WidgetQueryContentEvent caretRect(true, eQueryCaretRect, mWidget);
     caretRect.InitForQueryCaretRect(aRange.location);
     DispatchEvent(caretRect);
     if (!caretRect.mSucceeded) {
@@ -3978,7 +3978,7 @@ TextInputHandlerBase::SetSelection(NSRange& aRange)
   MOZ_ASSERT(!Destroyed());
 
   nsRefPtr<TextInputHandlerBase> kungFuDeathGrip(this);
-  WidgetSelectionEvent selectionEvent(true, NS_SELECTION_SET, mWidget);
+  WidgetSelectionEvent selectionEvent(true, eSetSelection, mWidget);
   selectionEvent.mOffset = aRange.location;
   selectionEvent.mLength = aRange.length;
   selectionEvent.mReversed = false;
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 5c048e3f0a..747cd01d34 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -1829,7 +1829,7 @@ nsChildView::ExecuteNativeKeyBinding(NativeKeyBindingsType aType,
   // the physical direction of the arrow.
   if (aEvent.keyCode >= nsIDOMKeyEvent::DOM_VK_LEFT &&
       aEvent.keyCode <= nsIDOMKeyEvent::DOM_VK_DOWN) {
-    WidgetQueryContentEvent query(true, NS_QUERY_SELECTED_TEXT, this);
+    WidgetQueryContentEvent query(true, eQuerySelectedText, this);
     DispatchWindowEvent(query);
 
     if (query.mSucceeded && query.mReply.mWritingMode.IsVertical()) {
@@ -1915,7 +1915,7 @@ NSView<mozView>* nsChildView::GetEditorView()
   // We need to get editor's view. E.g., when the focus is in the bookmark
   // dialog, the view is <panel> element of the dialog.  At this time, the key
   // events are processed the parent window's view that has native focus.
-  WidgetQueryContentEvent textContent(true, NS_QUERY_TEXT_CONTENT, this);
+  WidgetQueryContentEvent textContent(true, eQueryTextContent, this);
   textContent.InitForQueryTextContent(0, 0);
   DispatchWindowEvent(textContent);
   if (textContent.mSucceeded && textContent.mReply.mFocusedWidget) {
@@ -6080,8 +6080,7 @@ PanGestureTypeForEvent(NSEvent* aEvent)
     return NO;
 
   // Obtain the current selection.
-  WidgetQueryContentEvent event(true,
-                                NS_QUERY_SELECTION_AS_TRANSFERABLE,
+  WidgetQueryContentEvent event(true, eQuerySelectionAsTransferable,
                                 mGeckoChild);
   mGeckoChild->DispatchWindowEvent(event);
   if (!event.mSucceeded || !event.mReply.mTransferable)
diff --git a/widget/gtk/IMContextWrapper.cpp b/widget/gtk/IMContextWrapper.cpp
index 9c0d2fc11e..e4945538c6 100644
--- a/widget/gtk/IMContextWrapper.cpp
+++ b/widget/gtk/IMContextWrapper.cpp
@@ -94,6 +94,80 @@ public:
   virtual ~GetWritingModeName() {}
 };
 
+class GetTextRangeStyleText final : public nsAutoCString
+{
+public:
+    explicit GetTextRangeStyleText(const TextRangeStyle& aStyle)
+    {
+        if (!aStyle.IsDefined()) {
+            AssignLiteral("{ IsDefined()=false }");
+            return;
+        }
+
+        if (aStyle.IsLineStyleDefined()) {
+            AppendLiteral("{ mLineStyle=");
+            AppendLineStyle(aStyle.mLineStyle);
+            if (aStyle.IsUnderlineColorDefined()) {
+                AppendLiteral(", mUnderlineColor=");
+                AppendColor(aStyle.mUnderlineColor);
+            } else {
+                AppendLiteral(", IsUnderlineColorDefined=false");
+            }
+        } else {
+            AppendLiteral("{ IsLineStyleDefined()=false");
+        }
+
+        if (aStyle.IsForegroundColorDefined()) {
+            AppendLiteral(", mForegroundColor=");
+            AppendColor(aStyle.mForegroundColor);
+        } else {
+            AppendLiteral(", IsForegroundColorDefined()=false");
+        }
+
+        if (aStyle.IsBackgroundColorDefined()) {
+            AppendLiteral(", mBackgroundColor=");
+            AppendColor(aStyle.mBackgroundColor);
+        } else {
+            AppendLiteral(", IsBackgroundColorDefined()=false");
+        }
+
+        AppendLiteral(" }");
+    }
+    void AppendLineStyle(uint8_t aLineStyle)
+    {
+        switch (aLineStyle) {
+            case TextRangeStyle::LINESTYLE_NONE:
+                AppendLiteral("LINESTYLE_NONE");
+                break;
+            case TextRangeStyle::LINESTYLE_SOLID:
+                AppendLiteral("LINESTYLE_SOLID");
+                break;
+            case TextRangeStyle::LINESTYLE_DOTTED:
+                AppendLiteral("LINESTYLE_DOTTED");
+                break;
+            case TextRangeStyle::LINESTYLE_DASHED:
+                AppendLiteral("LINESTYLE_DASHED");
+                break;
+            case TextRangeStyle::LINESTYLE_DOUBLE:
+                AppendLiteral("LINESTYLE_DOUBLE");
+                break;
+            case TextRangeStyle::LINESTYLE_WAVY:
+                AppendLiteral("LINESTYLE_WAVY");
+                break;
+            default:
+                AppendPrintf("Invalid(0x%02X)", aLineStyle);
+                break;
+        }
+    }
+    void AppendColor(nscolor aColor)
+    {
+        AppendPrintf("{ R=0x%02X, G=0x%02X, B=0x%02X, A=0x%02X }",
+                     NS_GET_R(aColor), NS_GET_G(aColor), NS_GET_B(aColor),
+                     NS_GET_A(aColor));
+    }
+    virtual ~GetTextRangeStyleText() {};
+};
+
 const static bool kUseSimpleContextDefault = MOZ_WIDGET_GTK == 2;
 
 /******************************************************************************
@@ -1397,21 +1471,21 @@ IMContextWrapper::DispatchCompositionCommitEvent(
 
 already_AddRefed<TextRangeArray>
 IMContextWrapper::CreateTextRangeArray(GtkIMContext* aContext,
-                                       const nsAString& aLastDispatchedData)
+                                       const nsAString& aCompositionString)
 {
     MOZ_LOG(gGtkIMLog, LogLevel::Info,
         ("GTKIM: %p CreateTextRangeArray(aContext=%p, "
-         "aLastDispatchedData=\"%s\" (Length()=%u))",
-         this, aContext, NS_ConvertUTF16toUTF8(aLastDispatchedData).get(),
-         aLastDispatchedData.Length()));
+         "aCompositionString=\"%s\" (Length()=%u))",
+         this, aContext, NS_ConvertUTF16toUTF8(aCompositionString).get(),
+         aCompositionString.Length()));
 
     nsRefPtr<TextRangeArray> textRangeArray = new TextRangeArray();
 
     gchar *preedit_string;
-    gint cursor_pos;
+    gint cursor_pos_in_chars;
     PangoAttrList *feedback_list;
     gtk_im_context_get_preedit_string(aContext, &preedit_string,
-                                      &feedback_list, &cursor_pos);
+                                      &feedback_list, &cursor_pos_in_chars);
     if (!preedit_string || !*preedit_string) {
         MOZ_LOG(gGtkIMLog, LogLevel::Error,
             ("GTKIM: %p   CreateTextRangeArray(), FAILED, due to "
@@ -1422,6 +1496,53 @@ IMContextWrapper::CreateTextRangeArray(GtkIMContext* aContext,
         return textRangeArray.forget();
     }
 
+    // Convert caret offset from offset in characters to offset in UTF-16
+    // string.  If we couldn't proper offset in UTF-16 string, we should
+    // assume that the caret is at the end of the composition string.
+    uint32_t caretOffsetInUTF16 = aCompositionString.Length();
+    if (NS_WARN_IF(cursor_pos_in_chars < 0)) {
+        // Note that this case is undocumented.  We should assume that the
+        // caret is at the end of the composition string.
+    } else if (cursor_pos_in_chars == 0) {
+        caretOffsetInUTF16 = 0;
+    } else {
+        gchar* charAfterCaret =
+            g_utf8_offset_to_pointer(preedit_string, cursor_pos_in_chars);
+        if (NS_WARN_IF(!charAfterCaret)) {
+            MOZ_LOG(gGtkIMLog, LogLevel::Warning,
+                ("GTKIM: %p   CreateTextRangeArray(), failed to get UTF-8 "
+                 "string before the caret (cursor_pos_in_chars=%d)",
+                 this, cursor_pos_in_chars));
+        } else {
+            glong caretOffset = 0;
+            gunichar2* utf16StrBeforeCaret =
+                g_utf8_to_utf16(preedit_string, charAfterCaret - preedit_string,
+                                nullptr, &caretOffset, nullptr);
+            if (NS_WARN_IF(!utf16StrBeforeCaret) ||
+                NS_WARN_IF(caretOffset < 0)) {
+                MOZ_LOG(gGtkIMLog, LogLevel::Warning,
+                    ("GTKIM: %p   CreateTextRangeArray(), WARNING, failed to "
+                     "convert to UTF-16 string before the caret "
+                     "(cursor_pos_in_chars=%d, caretOffset=%d)",
+                     this, cursor_pos_in_chars, caretOffset));
+            } else {
+                caretOffsetInUTF16 = static_cast<uint32_t>(caretOffset);
+                uint32_t compositionStringLength = aCompositionString.Length();
+                if (NS_WARN_IF(caretOffsetInUTF16 > compositionStringLength)) {
+                    MOZ_LOG(gGtkIMLog, LogLevel::Warning,
+                        ("GTKIM: %p   CreateTextRangeArray(), WARNING, "
+                         "caretOffsetInUTF16=%u is larger than "
+                         "compositionStringLength=%u",
+                         this, caretOffsetInUTF16, compositionStringLength));
+                    caretOffsetInUTF16 = compositionStringLength;
+                }
+            }
+            if (utf16StrBeforeCaret) {
+                g_free(utf16StrBeforeCaret);
+            }
+        }
+    }
+
     PangoAttrIterator* iter;
     iter = pango_attr_list_get_iterator(feedback_list);
     if (!iter) {
@@ -1434,93 +1555,21 @@ IMContextWrapper::CreateTextRangeArray(GtkIMContext* aContext,
         return textRangeArray.forget();
     }
 
-    /*
-     * Depend on gtk2's implementation on XIM support.
-     * In aFeedback got from gtk2, there are only three types of data:
-     * PANGO_ATTR_UNDERLINE, PANGO_ATTR_FOREGROUND, PANGO_ATTR_BACKGROUND.
-     * Corresponding to XIMUnderline, XIMReverse.
-     * Don't take PANGO_ATTR_BACKGROUND into account, since
-     * PANGO_ATTR_BACKGROUND and PANGO_ATTR_FOREGROUND are always
-     * a couple.
-     */
     do {
-        PangoAttribute* attrUnderline =
-            pango_attr_iterator_get(iter, PANGO_ATTR_UNDERLINE);
-        PangoAttribute* attrForeground =
-            pango_attr_iterator_get(iter, PANGO_ATTR_FOREGROUND);
-        if (!attrUnderline && !attrForeground) {
+        TextRange range;
+        if (!SetTextRange(iter, preedit_string, caretOffsetInUTF16, range)) {
             continue;
         }
-
-        // Get the range of the current attribute(s)
-        gint start, end;
-        pango_attr_iterator_range(iter, &start, &end);
-
-        TextRange range;
-        // XIMReverse | XIMUnderline
-        if (attrUnderline && attrForeground) {
-            range.mRangeType = NS_TEXTRANGE_SELECTEDCONVERTEDTEXT;
-        }
-        // XIMUnderline
-        else if (attrUnderline) {
-            range.mRangeType = NS_TEXTRANGE_CONVERTEDTEXT;
-        }
-        // XIMReverse
-        else if (attrForeground) {
-            range.mRangeType = NS_TEXTRANGE_SELECTEDRAWTEXT;
-        } else {
-            range.mRangeType = NS_TEXTRANGE_RAWINPUT;
-        }
-
-        gunichar2* uniStr = nullptr;
-        if (start == 0) {
-            range.mStartOffset = 0;
-        } else {
-            glong uniStrLen;
-            uniStr = g_utf8_to_utf16(preedit_string, start,
-                                     nullptr, &uniStrLen, nullptr);
-            if (uniStr) {
-                range.mStartOffset = uniStrLen;
-                g_free(uniStr);
-                uniStr = nullptr;
-            }
-        }
-
-        glong uniStrLen;
-        uniStr = g_utf8_to_utf16(preedit_string + start, end - start,
-                                 nullptr, &uniStrLen, nullptr);
-        if (!uniStr) {
-            range.mEndOffset = range.mStartOffset;
-        } else {
-            range.mEndOffset = range.mStartOffset + uniStrLen;
-            g_free(uniStr);
-            uniStr = nullptr;
-        }
-
         textRangeArray->AppendElement(range);
-
-        MOZ_LOG(gGtkIMLog, LogLevel::Debug,
-            ("GTKIM: %p   CreateTextRangeArray(), mStartOffset=%u, "
-             "mEndOffset=%u, mRangeType=%s",
-             this, range.mStartOffset, range.mEndOffset,
-             GetRangeTypeName(range.mRangeType)));
     } while (pango_attr_iterator_next(iter));
 
     TextRange range;
-    if (cursor_pos < 0) {
-        range.mStartOffset = 0;
-    } else if (uint32_t(cursor_pos) > aLastDispatchedData.Length()) {
-        range.mStartOffset = aLastDispatchedData.Length();
-    } else {
-        range.mStartOffset = uint32_t(cursor_pos);
-    }
-    range.mEndOffset = range.mStartOffset;
+    range.mStartOffset = range.mEndOffset = caretOffsetInUTF16;
     range.mRangeType = NS_TEXTRANGE_CARETPOSITION;
     textRangeArray->AppendElement(range);
-
     MOZ_LOG(gGtkIMLog, LogLevel::Debug,
-        ("GTKIM: %p   CreateTextRangeArray(), mStartOffset=%u, mEndOffset=%u, "
-         "mRangeType=%s",
+        ("GTKIM: %p   CreateTextRangeArray(), mStartOffset=%u, "
+         "mEndOffset=%u, mRangeType=%s",
          this, range.mStartOffset, range.mEndOffset,
          GetRangeTypeName(range.mRangeType)));
 
@@ -1531,6 +1580,196 @@ IMContextWrapper::CreateTextRangeArray(GtkIMContext* aContext,
     return textRangeArray.forget();
 }
 
+/* static */
+nscolor
+IMContextWrapper::ToNscolor(PangoAttrColor* aPangoAttrColor)
+{
+    PangoColor& pangoColor = aPangoAttrColor->color;
+    uint8_t r = pangoColor.red / 0x100;
+    uint8_t g = pangoColor.green / 0x100;
+    uint8_t b = pangoColor.blue / 0x100;
+    return NS_RGB(r, g, b);
+}
+
+bool
+IMContextWrapper::SetTextRange(PangoAttrIterator* aPangoAttrIter,
+                               const gchar* aUTF8CompositionString,
+                               uint32_t aUTF16CaretOffset,
+                               TextRange& aTextRange) const
+{
+    // Set the range offsets in UTF-16 string.
+    gint utf8ClauseStart, utf8ClauseEnd;
+    pango_attr_iterator_range(aPangoAttrIter, &utf8ClauseStart, &utf8ClauseEnd);
+    if (utf8ClauseStart == utf8ClauseEnd) {
+        MOZ_LOG(gGtkIMLog, LogLevel::Error,
+            ("GTKIM: %p   SetTextRange(), FAILED, due to collapsed range",
+             this));
+        return false;
+    }
+
+    if (!utf8ClauseStart) {
+        aTextRange.mStartOffset = 0;
+    } else {
+        glong utf16PreviousClausesLength;
+        gunichar2* utf16PreviousClausesString =
+            g_utf8_to_utf16(aUTF8CompositionString, utf8ClauseStart, nullptr,
+                            &utf16PreviousClausesLength, nullptr);
+
+        if (NS_WARN_IF(!utf16PreviousClausesString)) {
+            MOZ_LOG(gGtkIMLog, LogLevel::Error,
+                ("GTKIM: %p   SetTextRange(), FAILED, due to g_utf8_to_utf16() "
+                 "failure (retrieving previous string of current clause)",
+                 this));
+            return false;
+        }
+
+        aTextRange.mStartOffset = utf16PreviousClausesLength;
+        g_free(utf16PreviousClausesString);
+    }
+
+    glong utf16CurrentClauseLength;
+    gunichar2* utf16CurrentClauseString =
+        g_utf8_to_utf16(aUTF8CompositionString + utf8ClauseStart,
+                        utf8ClauseEnd - utf8ClauseStart,
+                        nullptr, &utf16CurrentClauseLength, nullptr);
+
+    if (NS_WARN_IF(!utf16CurrentClauseString)) {
+        MOZ_LOG(gGtkIMLog, LogLevel::Error,
+            ("GTKIM: %p   SetTextRange(), FAILED, due to g_utf8_to_utf16() "
+             "failure (retrieving current clause)",
+             this));
+        return false;
+    }
+
+    aTextRange.mEndOffset = aTextRange.mStartOffset + utf16CurrentClauseLength;
+    g_free(utf16CurrentClauseString);
+    utf16CurrentClauseString = nullptr;
+
+    // Set styles
+    TextRangeStyle& style = aTextRange.mRangeStyle;
+
+    // Underline
+    PangoAttrInt* attrUnderline =
+        reinterpret_cast<PangoAttrInt*>(
+            pango_attr_iterator_get(aPangoAttrIter, PANGO_ATTR_UNDERLINE));
+    if (attrUnderline) {
+        switch (attrUnderline->value) {
+            case PANGO_UNDERLINE_NONE:
+                style.mLineStyle = TextRangeStyle::LINESTYLE_NONE;
+                break;
+            case PANGO_UNDERLINE_DOUBLE:
+                style.mLineStyle = TextRangeStyle::LINESTYLE_DOUBLE;
+                break;
+            case PANGO_UNDERLINE_ERROR:
+                style.mLineStyle = TextRangeStyle::LINESTYLE_WAVY;
+                break;
+            case PANGO_UNDERLINE_SINGLE:
+            case PANGO_UNDERLINE_LOW:
+                style.mLineStyle = TextRangeStyle::LINESTYLE_SOLID;
+                break;
+            default:
+                MOZ_LOG(gGtkIMLog, LogLevel::Warning,
+                    ("GTKIM: %p   SetTextRange(), retrieved unknown underline "
+                     "style: %d",
+                     this, attrUnderline->value));
+                style.mLineStyle = TextRangeStyle::LINESTYLE_SOLID;
+                break;
+        }
+        style.mDefinedStyles |= TextRangeStyle::DEFINED_LINESTYLE;
+
+        // Underline color
+        PangoAttrColor* attrUnderlineColor =
+            reinterpret_cast<PangoAttrColor*>(
+                pango_attr_iterator_get(aPangoAttrIter,
+                                        PANGO_ATTR_UNDERLINE_COLOR));
+        if (attrUnderlineColor) {
+            style.mUnderlineColor = ToNscolor(attrUnderlineColor);
+            style.mDefinedStyles |= TextRangeStyle::DEFINED_UNDERLINE_COLOR;
+        }
+    } else {
+        style.mLineStyle = TextRangeStyle::LINESTYLE_NONE;
+        style.mDefinedStyles |= TextRangeStyle::DEFINED_LINESTYLE;
+    }
+
+    // Don't set colors if they are not specified.  They should be computed by
+    // textframe if only one of the colors are specified.
+
+    // Foreground color (text color)
+    PangoAttrColor* attrForeground =
+        reinterpret_cast<PangoAttrColor*>(
+            pango_attr_iterator_get(aPangoAttrIter, PANGO_ATTR_FOREGROUND));
+    if (attrForeground) {
+        style.mForegroundColor = ToNscolor(attrForeground);
+        style.mDefinedStyles |= TextRangeStyle::DEFINED_FOREGROUND_COLOR;
+    }
+
+    // Background color
+    PangoAttrColor* attrBackground =
+        reinterpret_cast<PangoAttrColor*>(
+            pango_attr_iterator_get(aPangoAttrIter, PANGO_ATTR_BACKGROUND));
+    if (attrBackground) {
+        style.mBackgroundColor = ToNscolor(attrBackground);
+        style.mDefinedStyles |= TextRangeStyle::DEFINED_BACKGROUND_COLOR;
+    }
+
+    /**
+     * We need to judge the meaning of the clause for a11y.  Before we support
+     * IME specific composition string style, we used following rules:
+     *
+     *   1: If attrUnderline and attrForground are specified, we assumed the
+     *      clause is NS_TEXTRANGE_SELECTEDCONVERTEDTEXT.
+     *   2: If only attrUnderline is specified, we assumed the clause is
+     *      NS_TEXTRANGE_CONVERTEDTEXT.
+     *   3: If only attrForground is specified, we assumed the clause is
+     *      NS_TEXTRANGE_SELECTEDRAWTEXT.
+     *   4: If neither attrUnderline nor attrForeground is specified, we assumed
+     *      the clause is NS_TEXTRANGE_RAWINPUT.
+     *
+     * However, this rules are odd since there can be two or more selected
+     * clauses.  Additionally, our old rules caused that IME developers/users
+     * cannot specify composition string style as they want.
+     *
+     * So, we shouldn't guess the meaning from its visual style.
+     */
+
+    if (!attrUnderline && !attrForeground && !attrBackground) {
+        MOZ_LOG(gGtkIMLog, LogLevel::Warning,
+            ("GTKIM: %p   SetTextRange(), FAILED, due to no attr, "
+             "aTextRange= { mStartOffset=%u, mEndOffset=%u }",
+             this, aTextRange.mStartOffset, aTextRange.mEndOffset));
+        return false;
+    }
+
+    // If the range covers whole of composition string and the caret is at
+    // the end of the composition string, the range is probably not converted.
+    if (!utf8ClauseStart &&
+        utf8ClauseEnd == static_cast<gint>(strlen(aUTF8CompositionString)) &&
+        aTextRange.mEndOffset == aUTF16CaretOffset) {
+        aTextRange.mRangeType = NS_TEXTRANGE_RAWINPUT;
+    }
+    // Typically, the caret is set at the start of the selected clause.
+    // So, if the caret is in the clause, we can assume that the clause is
+    // selected.
+    else if (aTextRange.mStartOffset <= aUTF16CaretOffset &&
+             aTextRange.mEndOffset > aUTF16CaretOffset) {
+        aTextRange.mRangeType = NS_TEXTRANGE_SELECTEDCONVERTEDTEXT;
+    }
+    // Otherwise, we should assume that the clause is converted but not
+    // selected.
+    else {
+        aTextRange.mRangeType = NS_TEXTRANGE_CONVERTEDTEXT;
+    }
+
+    MOZ_LOG(gGtkIMLog, LogLevel::Debug,
+        ("GTKIM: %p   SetTextRange(), succeeded, aTextRange= { "
+         "mStartOffset=%u, mEndOffset=%u, mRangeType=%s, mRangeStyle=%s }",
+         this, aTextRange.mStartOffset, aTextRange.mEndOffset,
+         GetRangeTypeName(aTextRange.mRangeType),
+         GetTextRangeStyleText(aTextRange.mRangeStyle).get()));
+
+    return true;
+}
+
 void
 IMContextWrapper::SetCursorPosition(GtkIMContext* aContext)
 {
@@ -1571,7 +1810,7 @@ IMContextWrapper::SetCursorPosition(GtkIMContext* aContext)
     }
 
     WidgetQueryContentEvent charRect(true,
-                                     useCaret ? NS_QUERY_CARET_RECT :
+                                     useCaret ? eQueryCaretRect :
                                                 NS_QUERY_TEXT_RECT,
                                      mLastFocusedWindow);
     if (useCaret) {
@@ -1594,7 +1833,7 @@ IMContextWrapper::SetCursorPosition(GtkIMContext* aContext)
     if (!charRect.mSucceeded) {
         MOZ_LOG(gGtkIMLog, LogLevel::Error,
             ("GTKIM: %p   SetCursorPosition(), FAILED, %s was failed",
-             this, useCaret ? "NS_QUERY_CARET_RECT" : "NS_QUERY_TEXT_RECT"));
+             this, useCaret ? "eQueryCaretRect" : "NS_QUERY_TEXT_RECT"));
         return;
     }
 
@@ -1670,8 +1909,7 @@ IMContextWrapper::GetCurrentParagraph(nsAString& aText,
     }
 
     // Get all text contents of the focused editor
-    WidgetQueryContentEvent queryTextContentEvent(true,
-                                                  NS_QUERY_TEXT_CONTENT,
+    WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
                                                   mLastFocusedWindow);
     queryTextContentEvent.InitForQueryTextContent(0, UINT32_MAX);
     mLastFocusedWindow->DispatchEvent(&queryTextContentEvent, status);
@@ -1767,8 +2005,7 @@ IMContextWrapper::DeleteText(GtkIMContext* aContext,
     }
 
     // Get all text contents of the focused editor
-    WidgetQueryContentEvent queryTextContentEvent(true,
-                                                  NS_QUERY_TEXT_CONTENT,
+    WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
                                                   mLastFocusedWindow);
     queryTextContentEvent.InitForQueryTextContent(0, UINT32_MAX);
     mLastFocusedWindow->DispatchEvent(&queryTextContentEvent, status);
@@ -1814,7 +2051,7 @@ IMContextWrapper::DeleteText(GtkIMContext* aContext,
         g_utf8_offset_to_pointer(utf8Str.get(), endInUTF8Characters);
 
     // Set selection to delete
-    WidgetSelectionEvent selectionEvent(true, NS_SELECTION_SET,
+    WidgetSelectionEvent selectionEvent(true, eSetSelection,
                                         mLastFocusedWindow);
 
     nsDependentCSubstring utf8StrBeforeOffset(utf8Str, 0,
@@ -1913,7 +2150,7 @@ IMContextWrapper::EnsureToCacheSelection(nsAString* aSelectedString)
     }
 
     nsEventStatus status;
-    WidgetQueryContentEvent selection(true, NS_QUERY_SELECTED_TEXT,
+    WidgetQueryContentEvent selection(true, eQuerySelectedText,
                                       mLastFocusedWindow);
     InitEvent(selection);
     mLastFocusedWindow->DispatchEvent(&selection, status);
@@ -1962,7 +2199,7 @@ IMContextWrapper::Selection::Assign(const IMENotification& aIMENotification)
 void
 IMContextWrapper::Selection::Assign(const WidgetQueryContentEvent& aEvent)
 {
-    MOZ_ASSERT(aEvent.mMessage == NS_QUERY_SELECTED_TEXT);
+    MOZ_ASSERT(aEvent.mMessage == eQuerySelectedText);
     MOZ_ASSERT(aEvent.mSucceeded);
     mOffset = aEvent.mReply.mOffset;
     mLength = aEvent.mReply.mString.Length();
diff --git a/widget/gtk/IMContextWrapper.h b/widget/gtk/IMContextWrapper.h
index acc5922d26..f1933b39d8 100644
--- a/widget/gtk/IMContextWrapper.h
+++ b/widget/gtk/IMContextWrapper.h
@@ -345,13 +345,34 @@ protected:
      * Generates our text range array from current composition string.
      *
      * @param aContext              A GtkIMContext which is being handled.
-     * @param aLastDispatchedData   The data of the last compositionchange event
-     *                              of current composition.  This should be
-     *                              mDispatchedCompositionString.
+     * @param aCompositionString    The data to be dispatched with
+     *                              compositionchange event.
      */
     already_AddRefed<TextRangeArray>
         CreateTextRangeArray(GtkIMContext* aContext,
-                             const nsAString& aLastDispatchedData);
+                             const nsAString& aCompositionString);
+
+    /**
+     * SetTextRange() initializes aTextRange with aPangoAttrIter.
+     *
+     * @param aPangoAttrIter            An iter which represents a clause of the
+     *                                  composition string.
+     * @param aUTF8CompositionString    The whole composition string (UTF-8).
+     * @param aUTF16CaretOffset         The caret offset in the composition
+     *                                  string encoded as UTF-16.
+     * @param aTextRange                The result.
+     * @return                          true if this initializes aTextRange.
+     *                                  Otherwise, false.
+     */
+    bool SetTextRange(PangoAttrIterator* aPangoAttrIter,
+                      const gchar* aUTF8CompositionString,
+                      uint32_t aUTF16CaretOffset,
+                      TextRange& aTextRange) const;
+
+    /**
+     * ToNscolor() converts the PangoColor in aPangoAttrColor to nscolor.
+     */
+    static nscolor ToNscolor(PangoAttrColor* aPangoAttrColor);
 
     /**
      * Move the candidate window with "fake" cursor position.
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index 0acc582391..ad9d3f912b 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -5968,7 +5968,7 @@ nsWindow::ExecuteNativeKeyBinding(NativeKeyBindingsType aType,
 
         // Check if we're targeting content with vertical writing mode,
         // and if so remap the arrow keys.
-        WidgetQueryContentEvent query(true, NS_QUERY_SELECTED_TEXT, this);
+        WidgetQueryContentEvent query(true, eQuerySelectedText, this);
         nsEventStatus status;
         DispatchEvent(&query, status);
 
diff --git a/widget/tests/TestWinTSF.cpp b/widget/tests/TestWinTSF.cpp
index c80357975e..0bb71c55d9 100644
--- a/widget/tests/TestWinTSF.cpp
+++ b/widget/tests/TestWinTSF.cpp
@@ -1886,12 +1886,12 @@ TestApp::TestSelection(void)
   bool succeeded = true;
 
   /* If these fail the cause is probably one or more of:
-   * nsTextStore::GetSelection not sending NS_QUERY_SELECTED_TEXT
-   * NS_QUERY_SELECTED_TEXT not handled by ContentEventHandler
-   * Bug in NS_QUERY_SELECTED_TEXT handler
-   * nsTextStore::SetSelection not sending NS_SELECTION_SET
-   * NS_SELECTION_SET not handled by ContentEventHandler
-   * Bug in NS_SELECTION_SET handler
+   * nsTextStore::GetSelection not sending eQuerySelectedText
+   * eQuerySelectedText not handled by ContentEventHandler
+   * Bug in eQuerySelectedText handler
+   * nsTextStore::SetSelection not sending eSetSelection
+   * eSetSelection not handled by ContentEventHandler
+   * Bug in eSetSelection handler
    */
 
   TS_SELECTION_ACP testSel;
@@ -1960,12 +1960,12 @@ TestApp::TestText(void)
   HRESULT hr;
 
   /* If these fail the cause is probably one or more of:
-   * nsTextStore::GetText not sending NS_QUERY_TEXT_CONTENT
-   * NS_QUERY_TEXT_CONTENT not handled by ContentEventHandler
-   * Bug in NS_QUERY_TEXT_CONTENT handler
+   * nsTextStore::GetText not sending eQueryTextContent
+   * eQueryTextContent not handled by ContentEventHandler
+   * Bug in eQueryTextContent handler
    * nsTextStore::SetText not calling SetSelection or InsertTextAtSelection
    * Bug in SetSelection or InsertTextAtSelection
-   *  NS_SELECTION_SET bug or NS_COMPOSITION_* / NS_COMPOSITION_CHANGE bug
+   *  eSetSelection bug or NS_COMPOSITION_* / NS_COMPOSITION_CHANGE bug
    */
 
   if (!mMgr->GetFocusedStore()) {
diff --git a/widget/windows/IMMHandler.cpp b/widget/windows/IMMHandler.cpp
index 7f37c8c86f..043c1855fa 100644
--- a/widget/windows/IMMHandler.cpp
+++ b/widget/windows/IMMHandler.cpp
@@ -1726,14 +1726,13 @@ IMMHandler::HandleDocumentFeed(nsWindow* aWindow,
   }
 
   // Get all contents of the focused editor.
-  WidgetQueryContentEvent textContent(true, NS_QUERY_TEXT_CONTENT, aWindow);
+  WidgetQueryContentEvent textContent(true, eQueryTextContent, aWindow);
   textContent.InitForQueryTextContent(0, UINT32_MAX);
   aWindow->InitEvent(textContent, &point);
   aWindow->DispatchWindowEvent(&textContent);
   if (!textContent.mSucceeded) {
     MOZ_LOG(gIMMLog, LogLevel::Error,
-      ("IMM: HandleDocumentFeed, FAILED, due to NS_QUERY_TEXT_CONTENT "
-       "failure"));
+      ("IMM: HandleDocumentFeed, FAILED, due to eQueryTextContent failure"));
     return false;
   }
 
@@ -2203,13 +2202,13 @@ IMMHandler::GetCaretRect(nsWindow* aWindow,
     return false;
   }
 
-  WidgetQueryContentEvent caretRect(true, NS_QUERY_CARET_RECT, aWindow);
+  WidgetQueryContentEvent caretRect(true, eQueryCaretRect, aWindow);
   caretRect.InitForQueryCaretRect(selection.mOffset);
   aWindow->InitEvent(caretRect, &point);
   aWindow->DispatchWindowEvent(&caretRect);
   if (!caretRect.mSucceeded) {
     MOZ_LOG(gIMMLog, LogLevel::Info,
-      ("IMM: GetCaretRect, FAILED, due to NS_QUERY_CARET_RECT failure"));
+      ("IMM: GetCaretRect, FAILED, due to eQueryCaretRect failure"));
     return false;
   }
   aCaretRect = LayoutDevicePixel::ToUntyped(caretRect.mReply.mRect);
@@ -2753,14 +2752,13 @@ IMMHandler::Selection::Init(nsWindow* aWindow)
 {
   Clear();
 
-  WidgetQueryContentEvent selection(true, NS_QUERY_SELECTED_TEXT, aWindow);
+  WidgetQueryContentEvent selection(true, eQuerySelectedText, aWindow);
   nsIntPoint point(0, 0);
   aWindow->InitEvent(selection, &point);
   aWindow->DispatchWindowEvent(&selection);
   if (NS_WARN_IF(!selection.mSucceeded)) {
     MOZ_LOG(gIMMLog, LogLevel::Error,
-      ("IMM: Selection::Init, FAILED, due to NS_QUERY_SELECTED_TEXT "
-       "failure"));
+      ("IMM: Selection::Init, FAILED, due to eQuerySelectedText failure"));
     return false;
   }
   // If the window is destroyed during querying selected text, we shouldn't
diff --git a/widget/windows/TSFTextStore.cpp b/widget/windows/TSFTextStore.cpp
index 1cef5fcdd3..8383a83ba4 100644
--- a/widget/windows/TSFTextStore.cpp
+++ b/widget/windows/TSFTextStore.cpp
@@ -1301,7 +1301,7 @@ TSFTextStore::TSFTextStore()
   , mPendingOnSelectionChange(false)
   , mPendingOnLayoutChange(false)
   , mPendingDestroy(false)
-  , mPendingClearLockedContent(false)
+  , mDeferClearingLockedContent(false)
   , mNativeCaretIsCreated(false)
   , mDeferNotifyingTSF(false)
 {
@@ -1674,11 +1674,6 @@ TSFTextStore::FlushPendingActions()
     return;
   }
 
-  // If dispatching event causes NOTIFY_IME_OF_COMPOSITION_UPDATE, we should
-  // wait to abandon mLockedContent until it's notified because the dispatched
-  // event may be handled asynchronously in e10s mode.
-  mPendingClearLockedContent = !mPendingActions.Length();
-
   nsRefPtr<nsWindowBase> kungFuDeathGrip(mWidget);
   for (uint32_t i = 0; i < mPendingActions.Length(); i++) {
     PendingAction& action = mPendingActions[i];
@@ -1692,7 +1687,7 @@ TSFTextStore::FlushPendingActions()
 
         if (action.mAdjustSelection) {
           // Select composition range so the new composition replaces the range
-          WidgetSelectionEvent selectionSet(true, NS_SELECTION_SET, mWidget);
+          WidgetSelectionEvent selectionSet(true, eSetSelection, mWidget);
           mWidget->InitEvent(selectionSet);
           selectionSet.mOffset = static_cast<uint32_t>(action.mSelectionStart);
           selectionSet.mLength = static_cast<uint32_t>(action.mSelectionLength);
@@ -1701,7 +1696,7 @@ TSFTextStore::FlushPendingActions()
           if (!selectionSet.mSucceeded) {
             MOZ_LOG(sTextStoreLog, LogLevel::Error,
                    ("TSF: 0x%p   TSFTextStore::FlushPendingActions() "
-                    "FAILED due to NS_SELECTION_SET failure", this));
+                    "FAILED due to eSetSelection failure", this));
             break;
           }
         }
@@ -1712,7 +1707,9 @@ TSFTextStore::FlushPendingActions()
                                                 mWidget);
         mWidget->InitEvent(compositionStart);
         // NS_COMPOSITION_START always causes NOTIFY_IME_OF_COMPOSITION_UPDATE.
-        mPendingClearLockedContent = true;
+        // Therefore, we should wait to clear the locked content until it's
+        // notified.
+        mDeferClearingLockedContent = true;
         DispatchEvent(compositionStart);
         if (!mWidget || mWidget->Destroyed()) {
           break;
@@ -1777,9 +1774,11 @@ TSFTextStore::FlushPendingActions()
         }
         compositionChange.mRanges = action.mRanges;
         // When the NS_COMPOSITION_CHANGE causes a DOM text event,
-        // NOTIFY_IME_OF_COMPOSITION_UPDATE will be notified.
+        // the IME will be notified of NOTIFY_IME_OF_COMPOSITION_UPDATE.  In
+        // such case, we should not clear the locked content until we notify
+        // the IME of the composition update.
         if (compositionChange.CausesDOMTextEvent()) {
-          mPendingClearLockedContent = true;
+          mDeferClearingLockedContent = true;
         }
         DispatchEvent(compositionChange);
         // Be aware, the mWidget might already have been destroyed.
@@ -1802,9 +1801,11 @@ TSFTextStore::FlushPendingActions()
         mWidget->InitEvent(compositionCommit);
         compositionCommit.mData = action.mData;
         // When the NS_COMPOSITION_COMMIT causes a DOM text event,
-        // NOTIFY_IME_OF_COMPOSITION_UPDATE will be notified.
+        // the IME will be notified of NOTIFY_IME_OF_COMPOSITION_UPDATE.  In
+        // such case, we should not clear the locked content until we notify
+        // the IME of the composition update.
         if (compositionCommit.CausesDOMTextEvent()) {
-          mPendingClearLockedContent = true;
+          mDeferClearingLockedContent = true;
         }
         DispatchEvent(compositionCommit);
         if (!mWidget || mWidget->Destroyed()) {
@@ -1812,15 +1813,15 @@ TSFTextStore::FlushPendingActions()
         }
         break;
       }
-      case PendingAction::SELECTION_SET: {
+      case PendingAction::SET_SELECTION: {
         MOZ_LOG(sTextStoreLog, LogLevel::Debug,
                ("TSF: 0x%p   TSFTextStore::FlushPendingActions() "
-                "flushing SELECTION_SET={ mSelectionStart=%d, "
+                "flushing SET_SELECTION={ mSelectionStart=%d, "
                 "mSelectionLength=%d, mSelectionReversed=%s }",
                 this, action.mSelectionStart, action.mSelectionLength,
                 GetBoolName(action.mSelectionReversed)));
 
-        WidgetSelectionEvent selectionSet(true, NS_SELECTION_SET, mWidget);
+        WidgetSelectionEvent selectionSet(true, eSetSelection, mWidget);
         selectionSet.mOffset = 
           static_cast<uint32_t>(action.mSelectionStart);
         selectionSet.mLength =
@@ -1868,9 +1869,11 @@ TSFTextStore::MaybeFlushPendingNotifications()
     return;
   }
 
-  if (mPendingClearLockedContent) {
-    mPendingClearLockedContent = false;
+  if (!mDeferClearingLockedContent && mLockedContent.IsInitialized()) {
     mLockedContent.Clear();
+    MOZ_LOG(sTextStoreLog, LogLevel::Debug,
+           ("TSF: 0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+            "mLockedContent is cleared", this));
   }
 
   if (mPendingOnLayoutChange) {
@@ -1997,12 +2000,21 @@ TSFTextStore::LockedContent()
   // This should be called when the document is locked or the content hasn't
   // been abandoned yet.
   if (NS_WARN_IF(!IsReadLocked() && !mLockedContent.IsInitialized())) {
+    MOZ_LOG(sTextStoreLog, LogLevel::Error,
+           ("TSF: 0x%p   TSFTextStore::LockedContent(), FAILED, due to "
+            "called wrong timing, IsReadLocked()=%s, "
+            "mLockedContent.IsInitialized()=%s",
+            this, GetBoolName(IsReadLocked()),
+            GetBoolName(mLockedContent.IsInitialized())));
     mLockedContent.Clear();
     return mLockedContent;
   }
 
   Selection& currentSel = CurrentSelection();
   if (currentSel.IsDirty()) {
+    MOZ_LOG(sTextStoreLog, LogLevel::Error,
+           ("TSF: 0x%p   TSFTextStore::LockedContent(), FAILED, due to "
+            "CurrentSelection() failure", this));
     mLockedContent.Clear();
     return mLockedContent;
   }
@@ -2010,19 +2022,31 @@ TSFTextStore::LockedContent()
   if (!mLockedContent.IsInitialized()) {
     nsAutoString text;
     if (NS_WARN_IF(!GetCurrentText(text))) {
+      MOZ_LOG(sTextStoreLog, LogLevel::Error,
+             ("TSF: 0x%p   TSFTextStore::LockedContent(), FAILED, due to "
+              "GetCurrentText() failure", this));
       mLockedContent.Clear();
       return mLockedContent;
     }
 
     mLockedContent.Init(text);
+    // Basically, the locked content should be cleared after the document is
+    // unlocked.  However, in e10s mode, content will be modified
+    // asynchronously.  In such case, mDeferClearingLockedContent may be
+    // true even after the document is unlocked.
+    mDeferClearingLockedContent = false;
   }
 
   MOZ_LOG(sTextStoreLog, LogLevel::Debug,
          ("TSF: 0x%p   TSFTextStore::LockedContent(): "
-          "mLockedContent={ mText.Length()=%d, mLastCompositionString=\"%s\", "
+          "mLockedContent={ mText=\"%s\" (Length()=%u), "
+          "mLastCompositionString=\"%s\" (Length()=%u), "
           "mMinTextModifiedOffset=%u }",
-          this, mLockedContent.Text().Length(),
+          this, mLockedContent.Text().Length() <= 20 ?
+            NS_ConvertUTF16toUTF8(mLockedContent.Text()).get() : "<omitted>",
+          mLockedContent.Text().Length(),
           NS_ConvertUTF16toUTF8(mLockedContent.LastCompositionString()).get(),
+          mLockedContent.LastCompositionString().Length(),
           mLockedContent.MinTextModifiedOffset()));
 
   return mLockedContent;
@@ -2038,11 +2062,18 @@ TSFTextStore::GetCurrentText(nsAString& aTextContent)
 
   MOZ_ASSERT(mWidget && !mWidget->Destroyed());
 
-  WidgetQueryContentEvent queryText(true, NS_QUERY_TEXT_CONTENT, mWidget);
+  MOZ_LOG(sTextStoreLog, LogLevel::Debug,
+         ("TSF: 0x%p   TSFTextStore::GetCurrentText(): "
+          "retrieving text from the content...", this));
+
+  WidgetQueryContentEvent queryText(true, eQueryTextContent, mWidget);
   queryText.InitForQueryTextContent(0, UINT32_MAX);
   mWidget->InitEvent(queryText);
   DispatchEvent(queryText);
   if (NS_WARN_IF(!queryText.mSucceeded)) {
+    MOZ_LOG(sTextStoreLog, LogLevel::Error,
+           ("TSF: 0x%p   TSFTextStore::GetCurrentText(), FAILED, due to "
+            "eQueryTextContent failure", this));
     aTextContent.Truncate();
     return false;
   }
@@ -2061,8 +2092,7 @@ TSFTextStore::CurrentSelection()
       MOZ_CRASH();
     }
 
-    WidgetQueryContentEvent querySelection(true, NS_QUERY_SELECTED_TEXT,
-                                           mWidget);
+    WidgetQueryContentEvent querySelection(true, eQuerySelectedText, mWidget);
     mWidget->InitEvent(querySelection);
     DispatchEvent(querySelection);
     NS_ENSURE_TRUE(querySelection.mSucceeded, mSelection);
@@ -2664,7 +2694,7 @@ TSFTextStore::SetSelectionInternal(const TS_SELECTION_ACP* pSelection,
 
   CompleteLastActionIfStillIncomplete();
   PendingAction* action = mPendingActions.AppendElement();
-  action->mType = PendingAction::SELECTION_SET;
+  action->mType = PendingAction::SET_SELECTION;
   action->mSelectionStart = pSelection->acpStart;
   action->mSelectionLength = pSelection->acpEnd - pSelection->acpStart;
   action->mSelectionReversed = (pSelection->style.ase == TS_AE_START);
@@ -4676,7 +4706,9 @@ TSFTextStore::OnUpdateCompositionInternal()
      "mDeferNotifyingTSF=%s",
      this, GetBoolName(mDeferNotifyingTSF)));
 
-  mPendingClearLockedContent = true;
+  // Now, all sent composition events are handled by the content even in
+  // e10s mode.
+  mDeferClearingLockedContent = false;
   mDeferNotifyingTSF = false;
   MaybeFlushPendingNotifications();
   return NS_OK;
@@ -4779,14 +4811,14 @@ TSFTextStore::CreateNativeCaret()
   //     collapsed, is it OK?
   uint32_t caretOffset = currentSel.MaxOffset();
 
-  WidgetQueryContentEvent queryCaretRect(true, NS_QUERY_CARET_RECT, mWidget);
+  WidgetQueryContentEvent queryCaretRect(true, eQueryCaretRect, mWidget);
   queryCaretRect.InitForQueryCaretRect(caretOffset);
   mWidget->InitEvent(queryCaretRect);
   DispatchEvent(queryCaretRect);
   if (!queryCaretRect.mSucceeded) {
     MOZ_LOG(sTextStoreLog, LogLevel::Error,
            ("TSF: 0x%p   TSFTextStore::CreateNativeCaret() FAILED due to "
-            "NS_QUERY_CARET_RECT failure (offset=%d)", this, caretOffset));
+            "eQueryCaretRect failure (offset=%d)", this, caretOffset));
     return;
   }
 
diff --git a/widget/windows/TSFTextStore.h b/widget/windows/TSFTextStore.h
index 410f2615ef..7e3c680db0 100644
--- a/widget/windows/TSFTextStore.h
+++ b/widget/windows/TSFTextStore.h
@@ -511,7 +511,7 @@ protected:
       COMPOSITION_START,
       COMPOSITION_UPDATE,
       COMPOSITION_END,
-      SELECTION_SET
+      SET_SELECTION
     };
     ActionType mType;
     // For compositionstart and selectionset
@@ -793,9 +793,9 @@ protected:
   // During the documet is locked, we shouldn't destroy the instance.
   // If this is true, the instance will be destroyed after unlocked.
   bool                         mPendingDestroy;
-  // If this is true, MaybeFlushPendingNotifications() will clear the
+  // If this is false, MaybeFlushPendingNotifications() will clear the
   // mLockedContent.
-  bool                         mPendingClearLockedContent;
+  bool                         mDeferClearingLockedContent;
   // While there is native caret, this is true.  Otherwise, false.
   bool                         mNativeCaretIsCreated;
   // While the instance is dispatching events, the event may not be handled