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

- Bug 1172264 - Mirror duration from the MDSM to the MediaDecoderReader and remove MDSM::GetDuration. r=jww (369a3d1b4)
- Bug 1172264 - Route mExplicitDuration directly from the mediasource code to MediaDecoder, and stop passing an argument to DurationChanged. r=pending=jww (b429dfe41)
- Bug 1172264 - Watch mStateMachineDuration, and stop manually firing DurationChanged. r=jww (54091368c)
- bug 1126065 - Make JS callers of ios.newChannel call ios.newChannel2 in dom/browser-element. r=sicking (8c38534ed)
- Bug 1144015 - (Browser API) mozbrowseropentab support. r=kchen (8b1eecb4e)
- Bug 1143650: Update webref failure links r=karlt (b3c94f173)
- Bug 1172264 - Mark WPT as succeeding. r=jya (664350c56)
- Bug 1141029 - Disabling mochitests on Mulet with parity to B2G Desktop for taskcluster. r=ahal (73bb186cb)
- Bug 1144080 - Disable mochitests on Mulet for TaskCluster. r=ahal (0b71b6a05)
- Bug 1145407: Add mochitests that cause multiple tracks of the same type to be placed in the same remote stream. r=mt (263770e16)
- Bug 1148649: Reenable video multistream mochitests on debug e10s. r=drno (f7674fe4a)
- part of Bug 1094764 - Implement AudioContext.suspend and friends. @ (baa450713)
- Bug 1166803 - Add an `msg` tag to mochitest.ini in dom/media/*. r=jesup (5284df8b2)
- Bug 1166659 - Add mochitest tags for webaudio and webrtc. r=jesup, r=padenot (f5424f26f)
- Bug 1087551: updated tests around addIceCandidate(). r=jib (f28cde40b)
- Bug 1169338 - Part 1: Re-enable a subset of the webrtc mochitests on B2G emulator and Mulet. r=mt (9c0f8c2da)
- Bug 1143827 - remove default stun server. r=abr,bsmedberg (f1e306a95)
- Bug 1169338 - Part 2: Extend ICE timeouts since mochitests are frequently run on systems that are performance constrained. r=mt (da6147576)
- Bug 1155493 - Part 1: Add CaretStateChangedEvent and corresponding utility function. r=roc, sr=smaug (9d710ad21)
- Bug 995394: Removed parts of BrowserElementPanning.js that are only used when APZ is disabled and added that to a separte file BrowserElementPanningAPZDisabled.js r=botond, a=RyanVM (8b76bca9f)
- Bug 1138252 - Load BrowserElementPanning.js only if touch events are enabled. r=botond (30f5f3197)
- Bug 1155493 - Part 2: Event hook for mozbrowser element. r=kanru (6f6db8248)
- Bug 1162844 - Add meta name="viewmode" to have configurable VR experiences. r=fabrice (07d6d0736)
- Bug 1163961 - Browser API: Page search. r=kchen, r=ehsan (df0c37dfa)
- Bug 1179718 - Convert BrowserElement.webidl to use CheckAllPermissions. r=bz (4a92b2c7d)
- Bug 1147819 - Any media element should be stopped by the AudioChannelService when the window is destroyed, r=ehsan (e949db77f)
- Bug 1153915 - Null check the window in AudioChannelService::WindowDestroyedEnumerator(); r=baku (b38261d9d)
- Bug 1089526 - Change speaker state. r=baku (8dbf54b04)
- Bug 1157121 - Add speaker status checking. r=baku (ec5416680)
- Bug 1037389 - add support for deviceId in gUM constraints (merged 11 patches). r=smaug, r=jesup (bc6f9640d)
- Bug 1180748 - Unbreak building with --disable-webrtc. r=jesup (b5d53b666)

dom/media/MediaDecoderStateMachine.cpp

@@ -1379,26 +1379,11 @@ bool MediaDecoderStateMachine::IsRealTime() const
   return mRealTime;
 }
 
-int64_t MediaDecoderStateMachine::GetDuration()
-{
-  AssertCurrentThreadInMonitor();
-  if (mDuration.Ref().isNothing() || Duration().IsInfinite()) {
-    return -1;
-  }
-
-  return Duration().ToMicroseconds();
-}
-
 void MediaDecoderStateMachine::RecomputeDuration()
 {
   MOZ_ASSERT(OnTaskQueue());
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
 
-  // We dispatch DurationChanged to the MediaDecoder when the duration changes
-  // sometime after initialization, unless it has already been fired by the code
-  // that set the new duration.
-  bool fireDurationChanged = false;
-
   TimeUnit duration;
   if (mExplicitDuration.Ref().isSome()) {
     double d = mExplicitDuration.Ref().ref();
@@ -1412,7 +1397,6 @@ void MediaDecoderStateMachine::RecomputeDuration()
     duration = TimeUnit::FromSeconds(d);
   } else if (mEstimatedDuration.Ref().isSome()) {
     duration = mEstimatedDuration.Ref().ref();
-    fireDurationChanged = true;
   } else if (mInfo.mMetadataDuration.isSome()) {
     duration = mInfo.mMetadataDuration.ref();
   } else {
@@ -1421,18 +1405,10 @@ void MediaDecoderStateMachine::RecomputeDuration()
 
   if (duration < mObservedDuration.Ref()) {
     duration = mObservedDuration;
-    fireDurationChanged = true;
   }
-  fireDurationChanged = fireDurationChanged && duration != Duration();
 
   MOZ_ASSERT(duration.ToMicroseconds() >= 0);
   mDuration = Some(duration);
-
-  if (fireDurationChanged) {
-    nsCOMPtr<nsIRunnable> event =
-      NS_NewRunnableMethodWithArg<TimeUnit>(mDecoder, &MediaDecoder::DurationChanged, duration);
-    AbstractThread::MainThread()->Dispatch(event.forget());
-  }
 }
 
 void MediaDecoderStateMachine::SetFragmentEndTime(int64_t aEndTime)