Add test to track the number of hit tests on various events

Source/core/rendering/RenderView.h

Index: Source/core/rendering/RenderView.h
diff --git a/Source/core/rendering/RenderView.h b/Source/core/rendering/RenderView.h
index 682cba953db46c8f52c66b16b024fa44c473633b..30062e3e49f5ad9a843a2a41cd47807cc5f71073 100644
--- a/Source/core/rendering/RenderView.h
+++ b/Source/core/rendering/RenderView.h
@@ -47,6 +47,10 @@ public:
     bool hitTest(const HitTestRequest&, HitTestResult&);
     bool hitTest(const HitTestRequest&, const HitTestLocation&, HitTestResult&);
 
+    // Returns the count of calls to HitTest since this was last called.
+    // Used by tests that catch unnecessary hit-tests.
+    unsigned hitTestCountDelta();
+
     virtual const char* renderName() const OVERRIDE { return "RenderView"; }
 
     virtual bool isRenderView() const OVERRIDE { return true; }
@@ -203,6 +207,8 @@ private:
 
     RenderQuote* m_renderQuoteHead;
     unsigned m_renderCounterCount;
+
+    unsigned m_hitTestCount;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderView, isRenderView());