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

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

Index: third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
diff --git a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
index f9db4cf808fc28ae868126c5ae87fe8477c24efc..cdc50f02cf23062285209d7194f85ed3876b1502 100644
--- a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
+++ b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
@@ -42,6 +42,7 @@
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/StyleEngine.h"
 #include "core/events/Event.h"
+#include "core/events/MouseEvent.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLVideoElement.h"
@@ -1818,6 +1819,20 @@ void CanvasRenderingContext2D::filterNeedsInvalidation()
     state().clearResolvedFilter();
 }
 
+std::pair<Element*, String> CanvasRenderingContext2D::getControlAndIdIfHitRegionExists(const LayoutPoint& location)
+{
+    LayoutBox* box = canvas()->layoutBox();
+    FloatPoint localPos = box->absoluteToLocal(FloatPoint(location), UseTransforms);
+    if (box->hasBorderOrPadding())
+        localPos.move(-box->contentBoxOffset());
+    localPos.scale(canvas()->width() / box->contentWidth(), canvas()->height() / box->contentHeight());
+
+    HitRegion* hitRegion = hitRegionAtPoint(localPos);
+    if (hitRegion)
+        return std::make_pair(hitRegion->control(), hitRegion->id());
+    return std::make_pair(nullptr, String());
+}
+
 String CanvasRenderingContext2D::textAlign() const
 {
     return textAlignName(state().textAlign());