DevTools: simplify JSONValues API, prepare to the OwnPtr migration.

third_party/WebKit/Source/core/inspector/InspectorBaseAgent.cpp

 /*
  * Copyright (C) 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 74 matching lines @@
 void InspectorAgentRegistry::clearFrontend()
 {
     for (size_t i = 0; i < m_agents.size(); i++)
         m_agents[i]->clearFrontend();
 }
 
 void InspectorAgentRegistry::restore(const String& savedState)
 {
     RefPtr<JSONValue> state = parseJSON(savedState);
     if (state)
-        m_state = state->asObject();
+        m_state = JSONObject::cast(state);
     if (!m_state)
         m_state = JSONObject::create();
 
     for (size_t i = 0; i < m_agents.size(); i++) {
         RefPtr<JSONObject> agentState = m_state->getObject(m_agents[i]->name());
         if (!agentState) {
             agentState = JSONObject::create();
             m_state->setObject(m_agents[i]->name(), agentState);
         }
         m_agents[i]->setState(agentState);
@@ skipping 35 matching lines @@
 }
 
 void InspectorAgentRegistry::didCommitLoadForLocalFrame(LocalFrame* frame)
 {
     for (size_t i = 0; i < m_agents.size(); i++)
         m_agents[i]->didCommitLoadForLocalFrame(frame);
 }
 
 } // namespace blink