Let the WebMediaPlayer decide whether to use overlay video.

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 196 matching lines @@
     // causes an ambiguity error at compile time. This class's constructor
     // ensures that both implementations return document, so return the result
     // of one of them here.
     using HTMLElement::executionContext;
 
     bool hasSingleSecurityOrigin() const { return webMediaPlayer() && webMediaPlayer()->hasSingleSecurityOrigin(); }
 
     bool isFullscreen() const;
     void enterFullscreen();
     void exitFullscreen();
+    virtual bool usesOverlayFullscreenVideo() const { return false; }
 
     bool hasClosedCaptions() const;
     bool closedCaptionsVisible() const;
     void setClosedCaptionsVisible(bool);
 
     static void setTextTrackKindUserPreferenceForAllMediaElements(Document*);
     void automaticTrackSelectionForUpdatedUserPreference();
 
     // Returns the MediaControls, or null if they have not been added yet.
     // Note that this can be non-null even if there is no controls attribute.
@@ skipping 314 matching lines @@
     bool m_delayingLoadForPreloadNone : 1;
 
     bool m_tracksAreReady : 1;
     bool m_haveVisibleTextTrack : 1;
     bool m_processingPreferenceChange : 1;
     bool m_remoteRoutesAvailable : 1;
     bool m_playingRemotely : 1;
     bool m_isFinalizing : 1;
     bool m_initialPlayWithoutUserGestures : 1;
     bool m_autoplayMediaCounted : 1;
+    // Whether this element is in overlay fullscreen mode.
+    bool m_inOverlayFullscreenVideo : 1;
 
     PersistentWillBeMember<AudioTrackList> m_audioTracks;
     PersistentWillBeMember<VideoTrackList> m_videoTracks;
     PersistentWillBeMember<TextTrackList> m_textTracks;
     PersistentHeapVectorWillBeHeapVector<Member<TextTrack>> m_textTracksWhenResourceSelectionBegan;
 
     OwnPtrWillBeMember<CueTimeline> m_cueTimeline;
 
 #if ENABLE(WEB_AUDIO)
     // This is a weak reference, since m_audioSourceNode holds a reference to us.
@@ skipping 63 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