Don't make :hover sticky on tap on sites that set a mobile viewport set

Source/core/rendering/HitTestRequest.h

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 20 matching lines @@
         ReadOnly = 1 << 1,
         Active = 1 << 2,
         Move = 1 << 3,
         Release = 1 << 4,
         IgnoreClipping = 1 << 5,
         SVGClipContent = 1 << 6,
         TouchEvent = 1 << 7,
         AllowChildFrameContent = 1 << 8,
         ChildFrameHitTest = 1 << 9,
         IgnorePointerEventsNone = 1 << 10,
+        Hover = 1 << 11,

[Rick Byers, 2014/11/17 22:00:10]

It's a little confusing to explicitly opt-in to hover, when Active, Move and
Release already normally imply Hover.

Perhaps instead we should invert this by adding a new 'Leave' flag which (when
applied on conjunction with Release) forces hover to be cleared.

I know the existing code isn't well commented here, but please add a comment
describing the meaning of this new bit since it's rather subtle.

     };
 
     typedef unsigned HitTestRequestType;
 
     HitTestRequest(HitTestRequestType requestType)
         : m_requestType(requestType)
     {
     }
 
     bool readOnly() const { return m_requestType & ReadOnly; }
     bool active() const { return m_requestType & Active; }
     bool move() const { return m_requestType & Move; }
     bool release() const { return m_requestType & Release; }
     bool ignoreClipping() const { return m_requestType & IgnoreClipping; }
     bool svgClipContent() const { return m_requestType & SVGClipContent; }
     bool touchEvent() const { return m_requestType & TouchEvent; }
     bool allowsChildFrameContent() const { return m_requestType & AllowChildFrameContent; }
     bool isChildFrameHitTest() const { return m_requestType & ChildFrameHitTest; }
     bool ignorePointerEventsNone() const { return m_requestType & IgnorePointerEventsNone; }
+    bool hover() const { return m_requestType & Hover; }
 
     // Convenience functions
     bool touchMove() const { return move() && touchEvent(); }
 
     HitTestRequestType type() const { return m_requestType; }
 
 private:
     HitTestRequestType m_requestType;
 };
 
 } // namespace blink
 
 #endif // HitTestRequest_h