Implement a Hit Test Cache.

Source/core/paint/DeprecatedPaintLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 214 matching lines @@
 
     // Does the same as convertToLayerCoords() when not in multicol. For multicol, however,
     // convertToLayerCoords() calculates the offset in flow-thread coordinates (what the layout
     // engine uses internally), while this method calculates the visual coordinates; i.e. it figures
     // out which column the layer starts in and adds in the offset. See
     // http://www.chromium.org/developers/design-documents/multi-column-layout for more info.
     LayoutPoint visualOffsetFromAncestor(const DeprecatedPaintLayer* ancestorLayer) const;
 
     // The hitTest() method looks for mouse events by walking layers that intersect the point from front to back.
     bool hitTest(HitTestResult&);
-    bool hitTest(const HitTestRequest&, const HitTestLocation&, HitTestResult&);
 
     // Pass offsetFromRoot if known.
     bool intersectsDamageRect(const LayoutRect& layerBounds, const LayoutRect& damageRect, const DeprecatedPaintLayer* rootLayer, const LayoutPoint* offsetFromRoot = 0) const;
 
     // Bounding box relative to some ancestor layer. Pass offsetFromRoot if known.
     LayoutRect physicalBoundingBox(const DeprecatedPaintLayer* ancestorLayer, const LayoutPoint* offsetFromRoot = 0) const;
     LayoutRect physicalBoundingBoxIncludingReflectionAndStackingChildren(const DeprecatedPaintLayer* ancestorLayer, const LayoutPoint& offsetFromRoot) const;
     LayoutRect fragmentsBoundingBox(const DeprecatedPaintLayer* ancestorLayer) const;
 
     LayoutRect boundingBoxForCompositingOverlapTest() const;
@@ skipping 477 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::DeprecatedPaintLayer*);
 void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif // Layer_h