import from UXP: Issue #732 - Add a horizontal scroll action option for mouse wheel. (4932cf3e)

application/basilisk/app/profile/firefox.js

@@ -576,9 +576,10 @@ pref("browser.gesture.tap", "cmd_fullZoomReset");
 pref("browser.snapshots.limit", 0);
 
 // 0: Nothing happens
-// 1: Scrolling contents
+// 1: Scroll contents
 // 2: Go back or go forward, in your history
-// 3: Zoom in or out.
+// 3: Zoom in or out
+// 4: Scroll contents with X and Y swapped
 #ifdef XP_MACOSX
 // On OS X, if the wheel has one axis only, shift+wheel comes through as a
 // horizontal scroll event. Thus, we can't assign anything other than normal

dom/events/EventStateManager.cpp

@@ -3191,6 +3191,12 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
         action = WheelPrefs::GetInstance()->ComputeActionFor(wheelEvent);
       }
       switch (action) {
+        case WheelPrefs::ACTION_HSCROLL: {
+          // Swap axes and fall through
+          double deltaX = wheelEvent->mDeltaX;
+          wheelEvent->mDeltaX = wheelEvent->mDeltaY;
+          wheelEvent->mDeltaY = deltaX;
+        }
         case WheelPrefs::ACTION_SCROLL: {
           // For scrolling of default action, we should honor the mouse wheel
           // transaction.

dom/events/EventStateManager.h

@@ -513,7 +513,8 @@ protected:
       ACTION_SCROLL,
       ACTION_HISTORY,
       ACTION_ZOOM,
-      ACTION_LAST = ACTION_ZOOM,
+      ACTION_HSCROLL,
+      ACTION_LAST = ACTION_HSCROLL,
       // Following actions are used only by internal processing.  So, cannot
       // specified by prefs.
       ACTION_SEND_TO_PLUGIN