Bug 1117295 - Don't finish the source stream in MediaEngineDefault::Stop due to racy behavior. r=jesup

dom/media/webrtc/MediaEngineDefault.cpp

@@ -181,7 +181,6 @@ MediaEngineDefaultVideoSource::Stop(SourceMediaStream *aSource, TrackID aID)
       aSource->EndTrack(kTrackCount + i);
     }
   }
-  aSource->Finish();
 
   mState = kStopped;
   return NS_OK;
@@ -438,7 +437,6 @@ MediaEngineDefaultAudioSource::Stop(SourceMediaStream *aSource, TrackID aID)
       aSource->EndTrack(kTrackCount + kFakeVideoTrackCount+i);
     }
   }
-  aSource->Finish();
 
   mState = kStopped;
   return NS_OK;