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

Source/core/rendering/HitTestRequest.h

Index: Source/core/rendering/HitTestRequest.h
diff --git a/Source/core/rendering/HitTestRequest.h b/Source/core/rendering/HitTestRequest.h
index 272c0a20222eae54294974dbc9b874fcbcb852bf..84f4ea7f139316d50012e7a6a568156a8698e1c2 100644
--- a/Source/core/rendering/HitTestRequest.h
+++ b/Source/core/rendering/HitTestRequest.h
@@ -38,6 +38,7 @@ public:
         AllowChildFrameContent = 1 << 8,
         ChildFrameHitTest = 1 << 9,
         IgnorePointerEventsNone = 1 << 10,
+        Leave = 1 << 11, // forces :hover to be cleared
     };
 
     typedef unsigned HitTestRequestType;
@@ -57,6 +58,7 @@ public:
     bool allowsChildFrameContent() const { return m_requestType & AllowChildFrameContent; }
     bool isChildFrameHitTest() const { return m_requestType & ChildFrameHitTest; }
     bool ignorePointerEventsNone() const { return m_requestType & IgnorePointerEventsNone; }
+    bool leave() const { return m_requestType & Leave; }
 
     // Convenience functions
     bool touchMove() const { return move() && touchEvent(); }