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

Source/core/inspector/InspectorResourceContentLoader.h

Index: Source/core/inspector/InspectorResourceContentLoader.h
diff --git a/Source/core/inspector/InspectorResourceContentLoader.h b/Source/core/inspector/InspectorResourceContentLoader.h
index c781e20d032bd748b5bf527e5e99b93c7f9ede9b..ef27d9d714d5a981f973cf7a0224f62e15996a10 100644
--- a/Source/core/inspector/InspectorResourceContentLoader.h
+++ b/Source/core/inspector/InspectorResourceContentLoader.h
@@ -22,7 +22,7 @@ class InspectorResourceContentLoader FINAL {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     InspectorResourceContentLoader(Page*);
-    void addListener(PassOwnPtr<VoidCallback>);
+    void ensureResourcesContentLoaded(PassOwnPtr<VoidCallback>);
     ~InspectorResourceContentLoader();
     bool hasFinished();
     void stop();
@@ -32,9 +32,12 @@ private:
 
     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;