Enable HitTestCache by default.

Source/core/layout/HitTestResult.cpp

 /*
  * Copyright (C) 2006, 2008, 2011 Apple Inc. All rights reserved.
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 93 matching lines @@
 
 HitTestResult& HitTestResult::operator=(const HitTestResult& other)
 {
     m_hitTestLocation = other.m_hitTestLocation;
     m_hitTestRequest = other.m_hitTestRequest;
     populateFromCachedResult(other);
 
     return *this;
 }
 
-unsigned HitTestResult::equalityScore(const HitTestResult& other) const
-{
-    return (m_hitTestRequest.equalForCacheability(other.m_hitTestRequest) << 7)
-        | ((m_innerNode == other.innerNode()) << 6)
-        | ((m_innerPossiblyPseudoNode == other.innerPossiblyPseudoNode()) << 5)
-        | ((m_pointInInnerNodeFrame == other.m_pointInInnerNodeFrame) << 4)
-        | ((m_localPoint == other.localPoint()) << 3)
-        | ((m_innerURLElement == other.URLElement()) << 2)
-        | ((m_scrollbar == other.scrollbar()) << 1)
-        | (m_isOverWidget == other.isOverWidget());
-}
-
 bool HitTestResult::equalForCacheability(const HitTestResult& other) const
 {
     return m_hitTestRequest.equalForCacheability(other.m_hitTestRequest)
         && m_innerNode == other.innerNode()
         && m_innerPossiblyPseudoNode == other.innerPossiblyPseudoNode()
         && m_pointInInnerNodeFrame == other.m_pointInInnerNodeFrame
         && m_localPoint == other.localPoint()
         && m_innerURLElement == other.URLElement()
         && m_scrollbar == other.scrollbar()
         && m_isOverWidget == other.isOverWidget();
@@ skipping 399 matching lines @@
     else if (isHTMLMapElement(m_innerNode))
         imageMapImageElement = toHTMLMapElement(m_innerNode)->imageElement();
 
     if (!imageMapImageElement)
         return m_innerNode.get();
 
     return imageMapImageElement;
 }
 
 } // namespace blink