Adds keyboard functionality for videos.

third_party/WebKit/Source/core/html/shadow/MediaControls.h

 /*
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011, 2012 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 98 matching lines @@
   void onDisableRemotePlaybackAttributeChanged() {
     refreshCastButtonVisibility();
   }
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   friend class MediaControlsMediaEventListener;
   friend class MediaControlsOrientationLockDelegateTest;
   friend class MediaControlsTest;
+  friend class HTMLMediaElement;

[mlamouri (slow - plz ping), 2017/02/16 17:13:54]

We have an ongoing project to split the close relationship between MediaControls
and HTMLMediaElement. I don't think we should add friends here :) MediaControls
should only access public methods from HTMLMediaElement. Ideally, only methods
available from HTMLMediaElement.idl.

[CJ, 2017/02/17 02:45:50]

I figured, I just wanted to start the conversation. It was either this or making
the startHideMediaControlsTimer() public (it is the only reason for friends
here). Would making startHideMediaControlsTimer() public be better? I did not
find a good public method that would reach into this functionality. I am open to
other suggestions though.

 
   void invalidate(Element*);
 
   class BatchedControlUpdate;
 
   explicit MediaControls(HTMLMediaElement&);
 
   void initializeControls();
 
   void makeOpaque();
@@ skipping 85 matching lines @@
   int m_panelWidth;
 
   bool m_keepShowingUntilTimerFires : 1;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(MediaControls, isMediaControls());
 
 }  // namespace blink
 
 #endif