Notify WebMediaPlayer when HTML video enters full screen.

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 182 matching lines @@
     // entering fullscreen, and the WebMediaPlayer is responsible for displaying
     // the video in enteredFullscreen().
     virtual bool supportsOverlayFullscreenVideo() { return false; }
     // Inform WebMediaPlayer when the element has entered/exited fullscreen.
     virtual void enteredFullscreen() { }
     virtual void exitedFullscreen() { }
 
     virtual void enabledAudioTracksChanged(const WebVector<TrackId>& enabledTrackIds) { }
     // |selectedTrackId| is null if no track is selected.
     virtual void selectedVideoTrackChanged(TrackId* selectedTrackId) { }
+
+    // Inform the WebMediaPlayer whether the media is in full screen display.
+    // The media could enter/exit full screen when either the element itself
+    // or its parent element enters/exits full screen.
+    virtual void updateMediaInFullscreen(bool isFullscreen) {}

[aelias_OOO_until_Jul13, 2016/08/10 01:14:59]

Please file a BUG= tracking the underlying feature, and show me a link to the
pending patchset intended to use this new API.

I surmise this is Chromecast code already existing in your private branch that
you're now upstreaming?  Could you link to a design doc for your upstreaming
plan or otherwise give me some context (I haven't heard what's happening with
Chromecast lately)?

One basic question I have is whether this is part of a project to imminently
upstream Chromecast to 100%, or whether you plan to leave the other half inside
the private branch indefinitely.  In my experience, landing "dead" code with an
pseudo-API surface exposed only to a private branch is not maintainable.  The
Blink web API is more of an implementation detail of content/ rather than a true
API with external commitments -- in general any 
third_party/WebKit/public/ API with no user in content/ is something we consider
a loose end that should be deleted, and likewise we should not be adding any new
dead code like this either.

[xjz, 2016/08/10 21:33:29]

There is no private branch. The other part should be in WebMediaPlayer, which is
not finalized yet. The design doc is still under working. Maybe please hold off
the review of this CL first. I'll update when the design doc is available.
Thanks!

[aelias_OOO_until_Jul13, 2016/08/10 21:55:12]

Good to hear, thanks!  Please ping me again when the patch that makes use of it
is uploaded.  (I like to review code end-to-end to get a better perspective and
possibly suggest cross-cutting changes.)

 };
 
 } // namespace blink
 
 #endif