Bug 1215447 - move flag setting from SeekStarted() to Seek(). r=roc.

dom/html/HTMLMediaElement.cpp

@@ -1590,6 +1590,11 @@ HTMLMediaElement::Seek(double aTime,
   //       MediaDecoderReaders.
 
   mPlayingBeforeSeek = IsPotentiallyPlaying();
+  // Set the Variable if the Seekstarted while active playing
+  if (mPlayingThroughTheAudioChannel) {
+    mPlayingThroughTheAudioChannelBeforeSeek = true;
+  }
+
   // The media backend is responsible for dispatching the timeupdate
   // event if it changes the playback position as a result of the seek.
   LOG(LogLevel::Debug, ("%p SetCurrentTime(%f) starting seek", this, aTime));
@@ -3545,10 +3550,6 @@ void HTMLMediaElement::PlaybackEnded()
 void HTMLMediaElement::SeekStarted()
 {
   DispatchAsyncEvent(NS_LITERAL_STRING("seeking"));
-  // Set the Variable if the Seekstarted while active playing
-  if(mPlayingThroughTheAudioChannel) {
-    mPlayingThroughTheAudioChannelBeforeSeek = true;
-  }
 }
 
 void HTMLMediaElement::SeekCompleted()