Don't allow text selection to start on a HTMLMediaElement

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 325 matching lines @@
 
     virtual bool supportsFocus() const override final;
     virtual bool isMouseFocusable() const override final;
     virtual bool rendererIsNeeded(const RenderStyle&) override;
     virtual RenderObject* createRenderer(RenderStyle*) override;
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) override final;
     virtual void didNotifySubtreeInsertionsToDocument() override;
     virtual void removedFrom(ContainerNode*) override final;
     virtual void didRecalcStyle(StyleRecalcChange) override final;
 
+    virtual bool canStartSelection() const override { return false; }
+
     virtual void didBecomeFullscreenElement() override final;
     virtual void willStopBeingFullscreenElement() override final;
     virtual bool isInteractiveContent() const override final;
     virtual void defaultEventHandler(Event*) override final;
 
     // ActiveDOMObject functions.
     virtual void stop() override final;
 
     virtual void updateDisplayState() { }
 
@@ skipping 274 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