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

third_party/WebKit/Source/core/events/DragEvent.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/events/DragEvent.h"
 
 #include "core/clipboard/DataTransfer.h"
 #include "core/dom/Element.h"
 #include "core/events/EventDispatcher.h"
 
@@ skipping 28 matching lines @@
 
 DragEvent::DragEvent(const AtomicString& eventType, bool canBubble, bool cancelable, PassRefPtrWillBeRawPtr<AbstractView> view,
     int detail, int screenX, int screenY, int windowX, int windowY,
     int movementX, int movementY,
     PlatformEvent::Modifiers modifiers,
     short button, unsigned short buttons, PassRefPtrWillBeRawPtr<EventTarget> relatedTarget,
     double platformTimeStamp, DataTransfer* dataTransfer,
     PlatformMouseEvent::SyntheticEventType syntheticEventType)
     : MouseEvent(eventType, canBubble, cancelable, view, detail, screenX, screenY,
         windowX, windowY, movementX, movementY, modifiers, button, buttons, relatedTarget,
-        platformTimeStamp, syntheticEventType)
+        platformTimeStamp, syntheticEventType, String())

[Rick Byers, 2016/03/10 21:36:29]

technically I think this is a bug - drag events are mouse events so the spec
requires they follow canvas hit testing rules also (and.  But dnd events are
pretty rarely used, I doubt anyone is really going to notice here.  Mind filing
a pri=3 bug (just in case anyone goes looking for a known issue)?  I wouldn't
suggest spending your time on fixing it at this point (maybe wait for feedback
once people start using canvas hit regions).

[zino, 2016/03/11 09:35:47]

Done.

     , m_dataTransfer(dataTransfer)
 
 {
 }
 
 DragEvent::DragEvent(const AtomicString& type, const DragEventInit& initializer)
     : MouseEvent(type, initializer)
     , m_dataTransfer(initializer.dataTransfer())
 {
 }
@@ skipping 34 matching lines @@
     return toDragEvent(EventDispatchMediator::event());
 }
 
 DispatchEventResult DragEventDispatchMediator::dispatchEvent(EventDispatcher& dispatcher) const
 {
     event().eventPath().adjustForRelatedTarget(dispatcher.node(), event().relatedTarget());
     return EventDispatchMediator::dispatchEvent(dispatcher);
 }
 
 } // namespace blink