Canvas2d: Implement rerouting event by hit region's control.

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 115 matching lines @@
     void loseContext(LostContextMode) override;
     void didSetSurfaceSize() override;
 
     void restoreCanvasMatrixClipStack(SkCanvas*) const override;
 
     // TaskObserver implementation
     void didProcessTask() override;
     void willProcessTask() override { }
 
     void styleDidChange(const ComputedStyle* oldStyle, const ComputedStyle& newStyle) override;
+    std::pair<Element*, String> getControlAndIdIfHitRegionExists(const LayoutPoint& location) override;
 
     // SVGResourceClient implementation
     void filterNeedsInvalidation() override;
 
     // BaseRenderingContext2D implementation
     bool originClean() const final;
     void setOriginTainted() final;
     bool wouldTaintOrigin(CanvasImageSource* source) final { return CanvasRenderingContext::wouldTaintOrigin(source); }
 
     int width() const final;
@@ skipping 68 matching lines @@
     HashMap<String, Font> m_fontsResolvedUsingCurrentStyle;
     bool m_pruneLocalFontCacheScheduled;
     ListHashSet<String> m_fontLRUList;
 };
 
 DEFINE_TYPE_CASTS(CanvasRenderingContext2D, CanvasRenderingContext, context, context->is2d(), context.is2d());
 
 } // namespace blink
 
 #endif // CanvasRenderingContext2D_h