[WIP] bindings: Introduce PropertyBag

Source/modules/mediastream/RTCSessionDescription.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
@@ skipping 32 matching lines @@
 }
 
 static String constructIllegalTypeExceptionMessage(const String& type)
 {
     return "Illegal value of attribute 'type' : " + type;
 }
 
 RTCSessionDescription* RTCSessionDescription::create(const Dictionary& descriptionInitDict, ExceptionState& exceptionState)
 {
     String type;
-    bool ok = DictionaryHelper::get(descriptionInitDict, "type", type);
+    bool ok = descriptionInitDict.get("type", type);
     if (ok && !verifyType(type)) {
         exceptionState.throwDOMException(TypeMismatchError, constructIllegalTypeExceptionMessage(type));
         return nullptr;
     }
 
     String sdp;
-    DictionaryHelper::get(descriptionInitDict, "sdp", sdp);
+    descriptionInitDict.get("sdp", sdp);
 
     return new RTCSessionDescription(WebRTCSessionDescription(type, sdp));
 }
 
 RTCSessionDescription* RTCSessionDescription::create(WebRTCSessionDescription webSessionDescription)
 {
     return new RTCSessionDescription(webSessionDescription);
 }
 
 RTCSessionDescription::RTCSessionDescription(WebRTCSessionDescription webSessionDescription)
@@ skipping 23 matching lines @@
 {
     m_webSessionDescription.setSDP(sdp);
 }
 
 WebRTCSessionDescription RTCSessionDescription::webSessionDescription()
 {
     return m_webSessionDescription;
 }
 
 } // namespace blink