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

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 1070 matching lines @@
         || element.hasTagName(HTMLNames::tbodyTag)
         || element.hasTagName(HTMLNames::tfootTag)
         || element.hasTagName(HTMLNames::trTag)
         || element.hasTagName(HTMLNames::tdTag)
         || element.hasTagName(HTMLNames::thTag))
         return true;
 
     return false;
 }
 
+std::pair<Element*, String> HTMLCanvasElement::getControlAndIdIfHitRegionExists(const LayoutPoint& location)
+{
+    if (m_context && m_context->is2d() && m_context->hitRegionsCount() > 0)

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

nit: move the hitRegionsCount check down into implementation of the method on
the context itself (callers shouldn't need to worry about this optimization).

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

Done.

+        return m_context->getControlAndIdIfHitRegionExists(location);
+    return std::make_pair(nullptr, String());
+}
+
 } // namespace blink