Make OffscreenCanvas an EventTarget

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 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 7279 matching lines @@
     synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, functionName, reason);
     return false;
   }
 
   return true;
 }
 
 void WebGLRenderingContextBase::dispatchContextLostEvent(TimerBase*) {
   WebGLContextEvent* event = WebGLContextEvent::create(
       EventTypeNames::webglcontextlost, false, true, "");
-  canvas()->dispatchEvent(event);
+  if (getOffscreenCanvas())
+    getOffscreenCanvas()->dispatchEvent(event);
+  else
+    canvas()->dispatchEvent(event);
   m_restoreAllowed = event->defaultPrevented();
   if (m_restoreAllowed && !m_isHidden) {
     if (m_autoRecoveryMethod == Auto)
       m_restoreTimer.startOneShot(0, BLINK_FROM_HERE);
   }
 }
 
 void WebGLRenderingContextBase::maybeRestoreContext(TimerBase*) {
   ASSERT(isContextLost());
 
@@ skipping 357 matching lines @@
 
 void WebGLRenderingContextBase::getHTMLOrOffscreenCanvas(
     HTMLCanvasElementOrOffscreenCanvas& result) const {
   if (canvas())
     result.setHTMLCanvasElement(canvas());
   else
     result.setOffscreenCanvas(getOffscreenCanvas());
 }
 
 }  // namespace blink