[Android] Added a runtime flag to enable autoplay of muted videos.

third_party/WebKit/Source/core/html/HTMLMediaElement.h

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 448 matching lines @@
 
     // If the user gesture is required, then this will remove it.  Note that
     // one should not generally call this method directly; use the one on
     // m_helper and give it a reason.
     void unlockUserGesture();
 
     // Return true if and only if a user gesture is requried for playback.  Even
     // if isLockedPendingUserGesture() return true, this might return false if
     // the requirement is currently overridden.  This does not check if a user
     // gesture is currently being processed.
-    bool isGestureNeededForPlayback() const;
+    bool isGestureNeededForPlayback();
 
     void setNetworkState(NetworkState);
 
     void audioTracksTimerFired(Timer<HTMLMediaElement>*);
 
     // TODO(liberato): remove once autoplay gesture override experiment concludes.
     void triggerAutoplayViewportCheckForTesting();
 
     void scheduleResolvePlayPromises();
     void scheduleRejectPlayPromises(ExceptionCode);
@@ skipping 188 matching lines @@
 inline bool isHTMLMediaElement(const HTMLElement& element)
 {
     return isHTMLAudioElement(element) || isHTMLVideoElement(element);
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 } // namespace blink
 
 #endif // HTMLMediaElement_h