Use event init dictionaries in core/{css,html}

Source/core/html/canvas/WebGLContextEvent.cpp

 /*
  * Copyright (C) 2010 Google 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
@@ skipping 10 matching lines @@
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/html/canvas/WebGLContextEvent.h"
 
 namespace blink {
 
-WebGLContextEventInit::WebGLContextEventInit()
-{
-}
-
 WebGLContextEvent::WebGLContextEvent()
 {
 }
 
 WebGLContextEvent::WebGLContextEvent(const AtomicString& type, bool canBubble, bool cancelable, const String& statusMessage)
     : Event(type, canBubble, cancelable)
     , m_statusMessage(statusMessage)
 {
 }
 
 WebGLContextEvent::WebGLContextEvent(const AtomicString& type, const WebGLContextEventInit& initializer)
     : Event(type, initializer)
-    , m_statusMessage(initializer.statusMessage)
 {
+    if (initializer.hasStatusMessage())
+        m_statusMessage = initializer.statusMessage();
 }
 
 WebGLContextEvent::~WebGLContextEvent()
 {
 }
 
 const AtomicString& WebGLContextEvent::interfaceName() const
 {
     return EventNames::WebGLContextEvent;
 }
 
 void WebGLContextEvent::trace(Visitor* visitor)
 {
     Event::trace(visitor);
 }
 
 } // namespace blink