Bug 1208316 - Rename MediaStreamTrack::NotifyEnded to OverrideEnded. r=jib

Better semantics for what I want to do with NotifyEnded in later patches in the bug.

MozReview-Commit-ID: 8X0BdiVncNo

dom/html/HTMLMediaElement.cpp

@@ -1362,7 +1362,7 @@ void HTMLMediaElement::NotifyMediaTrackDisabled(MediaTrack* aTrack)
         MOZ_ASSERT(outputTrack);
         if (outputTrack) {
           NS_DispatchToMainThread(
-            NewRunnableMethod(outputTrack, &MediaStreamTrack::NotifyEnded));
+            NewRunnableMethod(outputTrack, &MediaStreamTrack::OverrideEnded));
         }
 
         ms.mTrackPorts[i].second()->Destroy();