DevTools: Do not load css resources content before CSS agent is enabled.

Source/core/inspector/InspectorResourceContentLoader.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef InspectorResourceContentLoader_h
 #define InspectorResourceContentLoader_h
 
 #include "core/fetch/ResourcePtr.h"
 #include "wtf/HashSet.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class CSSStyleSheetResource;
 class Page;
 class Resource;
 class VoidCallback;
 
 class InspectorResourceContentLoader FINAL {
     WTF_MAKE_NONCOPYABLE(InspectorResourceContentLoader);
     WTF_MAKE_FAST_ALLOCATED;
 public:
     InspectorResourceContentLoader(Page*);
-    void addListener(PassOwnPtr<VoidCallback>);
+    void ensureResourcesContentLoaded(PassOwnPtr<VoidCallback>);
     ~InspectorResourceContentLoader();
     bool hasFinished();
     void stop();
 
 private:
     class ResourceClient;
 
     void resourceFinished(ResourceClient*);
     void checkDone();
+    void start();
 
     Vector<OwnPtr<VoidCallback> > m_callbacks;
     bool m_allRequestsStarted;
+    bool m_started;
+    Page* m_page;
     HashSet<ResourceClient*> m_pendingResourceClients;
     Vector<ResourcePtr<Resource> > m_resources;
 
     friend class ResourceClient;
 };
 
 } // namespace WebCore
 
 
 #endif // !defined(InspectorResourceContentLoader_h)