[Blink>Media] Add heuristic for dominant video detection for Android

third_party/WebKit/public/platform/WebMediaPlayer.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 252 matching lines @@
   // the video in enteredFullscreen().
   virtual bool supportsOverlayFullscreenVideo() { return false; }
   // Inform WebMediaPlayer when the element has entered/exited fullscreen.
   virtual void enteredFullscreen() {}
   virtual void exitedFullscreen() {}
 
   // Inform WebMediaPlayer when the element starts/stops being the dominant
   // visible content. This will only be called after the monitoring of the
   // intersection with viewport is activated by calling
   // WebMediaPlayerClient::activateViewportIntersectionMonitoring().
   virtual void becameDominantVisibleContent(bool isDominant) {}

[miu, 2017/02/24 22:44:39]

Can the old heuristic be removed? It seems the new one should work for our use
case as well as yours. :)

If you want to address that in a separate change, please put a TODO comment here
and file a crbug for tracking (cc'ing me and xjz).

Also, feel free to send us a patch and we can test it out on our end to make
sure all's well.

[Zhiqiang Zhang (Slow), 2017/02/25 18:48:27]

Filed a bug and added TODO :)

 
+  // Inform WebMediaPlayer when the element starts/stops being the effectively
+  // fullscreen video, i.e. being the fullscreen element or child of the
+  // fullscreen element, and being dominant in the viewport.
+  virtual void setIsEffectivelyFullscreen(bool) {}
+
   virtual void enabledAudioTracksChanged(
       const WebVector<TrackId>& enabledTrackIds) {}
   // |selectedTrackId| is null if no track is selected.
   virtual void selectedVideoTrackChanged(TrackId* selectedTrackId) {}
 };
 
 }  // namespace blink
 
 #endif