import changes from `dev' branch of rmottola/Arctic-Fox:

- fix patch ordering coming from PM repo (3a8768f44)
- Bug 1119074 - If we're stopping event propagation from XUL popups, also stop them from crossing process boundaries r=smaug,felipe (965e2193e)
- Bug 1082145 - |js::WatchGuts| can leak |wpmap|. r=erahm (12c86f3d3)
- No Bug - Improve Interpreter stack accessor assertions. (rs=Waldo) (8ba7a702c)
- Bug 874842 - Return Event instead of nsIDOMEvent (748b57fd2)
- Bug 1165966 - Add test cases r=terrence (79a909d5b)
- Bug 1167025: Do not mix bool and int in bitwise-or in blendpsMask; r=sunfish (f0f23c0c4)
- Bug 1158323 - Make sure we set a base rect on document elements that have margins set. r=tn (c253a2ef8)
- Bug 1178847 - Move the code from ChromeProcessController::InitializeRoot to APZCCallbackHelper so it can be reused in the child process. r=botond (16d539bcb)
- Bug 1165966 - Add error checking when populating safepoints r=bhackett (c66d249d1)
- spacing and pointer style (cddc1bac4)
- Bug 1196027 - check the actual current marking mode instead of the permanent intention, r=terrence (eddcfd7fb)
- Bug 1206590: Move gcWeakMapList from JSCompartment to JS::Zone. r=terrence (7e5e0d505)
- Bug 1181908 part 1. Fix support for JSOP_OBJECT in scripts parsed on background threads by clearing the unboxedLayouts list on the background thread parsing compartment when merging the parse result to the target compartment. r=jandem (25c6a3b01)
- Bug 1163207 - Make RematerializedFrame store the real callee. (r=shu) (ce276e91c)
- Bug 1164448 - Handle unwound rectifier frames as exit frames in JitProfilingFrameIterator. r=jandem (bb639b4e2)
- Bug 1164448 - Add test. r=jandem (83f5cc608)
- Bug 1196497 - Don't assert that the replacer continues to pass IsArray during JSON.stringify. (If the replacer was a revocable proxy to an array, revoking the proxy would make the replacer no longer IsArray.) r=evilpie (442c3823f)
- Bug 1177247 - Prevent HandlePossibleViewportChange from clobbering a restored scroll position from forward/back navigation. r=botond (4202ac757)
- Bug 1182772, optimize ProcessGlobal out from CC graph (and also TabChild's EventListeners), r=mccr8 (ccb2278bf)
- Bug 1139155 - Add a mechanism to know when the APZ is done processing. r=botond (17328e5be)
- Bug 1171537 - Allow URIs to be the empty string in TabParent::RecvCreateWindow. r=billm. (e280e994c)
- Bug 1173219 - Return nsresults from TabParent::RecvCreateWindow to make opening windows more robust. r=billm (9f0633b15)
- Bug 1142817 - Use UniquePtr in testXDR_sourceMap. r=erahm (7ec437162)

dom/base/nsDOMDataChannel.cpp

@@ -17,9 +17,9 @@ extern PRLogModuleInfo* GetDataChannelLog();
 #include "nsDOMDataChannelDeclarations.h"
 #include "nsDOMDataChannel.h"
 #include "nsIDOMDataChannel.h"
-#include "nsIDOMMessageEvent.h"
 #include "mozilla/DOMEventTargetHelper.h"
 #include "mozilla/dom/File.h"
+#include "mozilla/dom/MessageEvent.h"
 #include "mozilla/dom/ScriptSettings.h"
 
 #include "nsError.h"
@@ -401,20 +401,15 @@ nsDOMDataChannel::DoOnMessageAvailable(const nsACString& aData,
     jsData.setString(jsString);
   }
 
-  nsCOMPtr<nsIDOMEvent> event;
-  rv = NS_NewDOMMessageEvent(getter_AddRefs(event), this, nullptr, nullptr);
-  NS_ENSURE_SUCCESS(rv,rv);
+  nsRefPtr<MessageEvent> event = NS_NewDOMMessageEvent(this, nullptr, nullptr);
 
-  nsCOMPtr<nsIDOMMessageEvent> messageEvent = do_QueryInterface(event);
-  rv = messageEvent->InitMessageEvent(NS_LITERAL_STRING("message"),
-                                      false, false,
-                                      jsData, mOrigin, EmptyString(),
-                                      nullptr);
+  rv = event->InitMessageEvent(NS_LITERAL_STRING("message"), false, false,
+                               jsData, mOrigin, EmptyString(), nullptr);
   NS_ENSURE_SUCCESS(rv,rv);
   event->SetTrusted(true);
 
   LOG(("%p(%p): %s - Dispatching\n",this,(void*)mDataChannel,__FUNCTION__));
-  rv = DispatchDOMEvent(nullptr, event, nullptr, nullptr);
+  rv = DispatchDOMEvent(nullptr, static_cast<Event*>(event), nullptr, nullptr);
   if (NS_FAILED(rv)) {
     NS_WARNING("Failed to dispatch the message event!!!");
   }
@@ -447,9 +442,7 @@ nsDOMDataChannel::OnSimpleEvent(nsISupports* aContext, const nsAString& aName)
     return NS_OK;
   }
 
-  nsCOMPtr<nsIDOMEvent> event;
-  rv = NS_NewDOMEvent(getter_AddRefs(event), this, nullptr, nullptr);
-  NS_ENSURE_SUCCESS(rv,rv);
+  nsRefPtr<Event> event = NS_NewDOMEvent(this, nullptr, nullptr);
 
   rv = event->InitEvent(aName, false, false);
   NS_ENSURE_SUCCESS(rv,rv);