Split Dictionary's get and convert into DictionaryHelper.

Source/core/page/EventSource.cpp

 /*
  * Copyright (C) 2009, 2012 Ericsson AB. All rights reserved.
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011, Code Aurora Forum. 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
@@ skipping 51 matching lines @@
     , m_url(url)
     , m_withCredentials(false)
     , m_state(CONNECTING)
     , m_decoder(TextResourceDecoder::create("text/plain", "UTF-8"))
     , m_connectTimer(this, &EventSource::connectTimerFired)
     , m_discardTrailingNewline(false)
     , m_requestInFlight(false)
     , m_reconnectDelay(defaultReconnectDelay)
 {
     ScriptWrappable::init(this);
-    eventSourceInit.get("withCredentials", m_withCredentials);
+    DictionaryHelper::get(eventSourceInit, "withCredentials", m_withCredentials);
 }
 
 PassRefPtrWillBeRawPtr<EventSource> EventSource::create(ExecutionContext* context, const String& url, const Dictionary& eventSourceInit, ExceptionState& exceptionState)
 {
     if (url.isEmpty()) {
         exceptionState.throwDOMException(SyntaxError, "Cannot open an EventSource to an empty URL.");
         return nullptr;
     }
 
     KURL fullURL = context->completeURL(url);
@@ skipping 347 matching lines @@
 
 PassRefPtrWillBeRawPtr<MessageEvent> EventSource::createMessageEvent()
 {
     RefPtrWillBeRawPtr<MessageEvent> event = MessageEvent::create();
     event->initMessageEvent(m_eventName.isEmpty() ? EventTypeNames::message : m_eventName, false, false, SerializedScriptValue::create(String(m_data)), m_eventStreamOrigin, m_lastEventId, 0, nullptr);
     m_data.clear();
     return event.release();
 }
 
 } // namespace WebCore