Reapply 169371 "DevTools: defer styles delta calculation to until the end of the task"

Source/core/inspector/InspectorController.h

 /*
  * 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 103 matching lines @@
 
     bool isUnderTest();
     void evaluateForTestInFrontend(long callId, const String& script);
 
     void resume();
 
     void setResourcesDataSizeLimitsFromInternals(int maximumResourcesContentSize, int maximumSingleResourceContentSize);
 
     void willProcessTask();
     void didProcessTask();
+    void flushPendingFrontendMessages();
 
     void didCommitLoadForMainFrame();
     void didBeginFrame(int frameId);
     void didCancelFrame();
     void willComposite();
     void didComposite();
 
     void processGPUEvent(double timestamp, int phase, bool foreign, size_t usedGPUMemoryBytes);
 
     void scriptsEnabled(bool);
 
     void willAddPageOverlay(const GraphicsLayer*);
     void didRemovePageOverlay(const GraphicsLayer*);
+
 private:
     InspectorController(Page*, InspectorClient*);
 
     void initializeDeferredAgents();
 
     friend InstrumentingAgents* instrumentationForPage(Page*);
 
     RefPtr<InstrumentingAgents> m_instrumentingAgents;
     OwnPtr<InjectedScriptManager> m_injectedScriptManager;
     OwnPtr<InspectorCompositeState> m_state;
@@ skipping 12 matching lines @@
     InspectorAgentRegistry m_agents;
     Vector<InspectorAgent*> m_moduleAgents;
     bool m_isUnderTest;
     bool m_deferredAgentsInitialized;
 };
 
 }
 
 
 #endif // !defined(InspectorController_h)