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

Source/core/html/MediaKeyEvent.cpp

 /*
  * Copyright (C) 2012 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * 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/MediaKeyEvent.h"
 
 namespace blink {
 
-MediaKeyEventInit::MediaKeyEventInit()
-    : systemCode(0)
-{
-}
-
 MediaKeyEvent::MediaKeyEvent()
 {
 }
 
 MediaKeyEvent::MediaKeyEvent(const AtomicString& type, const MediaKeyEventInit& initializer)
     : Event(type, initializer)
-    , m_keySystem(initializer.keySystem)
-    , m_sessionId(initializer.sessionId)
-    , m_initData(initializer.initData)
-    , m_message(initializer.message)
-    , m_defaultURL(initializer.defaultURL)
-    , m_errorCode(initializer.errorCode)
-    , m_systemCode(initializer.systemCode)
+    , m_systemCode(0)
 {
+    if (initializer.hasKeySystem())
+        m_keySystem = initializer.keySystem();
+    if (initializer.hasSessionId())
+        m_sessionId = initializer.sessionId();
+    if (initializer.hasInitData())
+        m_initData = initializer.initData();
+    if (initializer.hasMessage())
+        m_message = initializer.message();
+    if (initializer.hasDefaultURL())
+        m_defaultURL = initializer.defaultURL();
+    if (initializer.hasErrorCode())
+        m_errorCode = initializer.errorCode();
+    if (initializer.hasSystemCode())
+        m_systemCode = initializer.systemCode();
 }
 
 MediaKeyEvent::~MediaKeyEvent()
 {
 }
 
 const AtomicString& MediaKeyEvent::interfaceName() const
 {
     return EventNames::MediaKeyEvent;
 }
 
 void MediaKeyEvent::trace(Visitor* visitor)
 {
     visitor->trace(m_errorCode);
     Event::trace(visitor);
 }
 
 } // namespace blink