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

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

Index: third_party/WebKit/Source/modules/canvas2d/MouseEventHitRegion.h
diff --git a/third_party/WebKit/Source/modules/canvas2d/MouseEventHitRegion.h b/third_party/WebKit/Source/modules/canvas2d/MouseEventHitRegion.h
index 2f213164d0a8e345055e3d18038dc017e6528615..85ac70c8cab0af46da8b33b9c34850398c20033b 100644
--- a/third_party/WebKit/Source/modules/canvas2d/MouseEventHitRegion.h
+++ b/third_party/WebKit/Source/modules/canvas2d/MouseEventHitRegion.h
@@ -5,14 +5,14 @@
 #ifndef MouseEventHitRegion_h
 #define MouseEventHitRegion_h
 
-#include "modules/canvas2d/EventHitRegion.h"
 #include "wtf/Allocator.h"
+#include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class MouseEvent;
 
-class MouseEventHitRegion : public EventHitRegion {
+class MouseEventHitRegion {
     STATIC_ONLY(MouseEventHitRegion);
 public:
     static String region(MouseEvent&);