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

Source/core/inspector/InspectorPageAgent.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 696 matching lines @@
 {
     String content;
     if (getEditedResourceContent(url, &content)) {
         callback->sendSuccess(content, false);
         return;
     }
     if (!m_inspectorResourceContentLoader) {
         callback->sendFailure("Agent is not enabled.");
         return;
     }
-    m_inspectorResourceContentLoader->addListener(adoptPtr(new GetResourceContentLoadListener(this, frameId, url, callback)));
+    m_inspectorResourceContentLoader->ensureResourcesContentLoaded(adoptPtr(new GetResourceContentLoadListener(this, frameId, url, callback)));
 }
 
 static bool textContentForResource(Resource* cachedResource, String* result)
 {
     if (hasTextContent(cachedResource)) {
         String content;
         bool base64Encoded;
         if (InspectorPageAgent::cachedResourceContent(cachedResource, result, &base64Encoded)) {
             ASSERT(!base64Encoded);
             return true;
@@ skipping 699 matching lines @@
 bool InspectorPageAgent::getEditedResourceContent(const String& url, String* content)
 {
     if (!m_editedResourceContent.contains(url))
         return false;
     *content = m_editedResourceContent.get(url);
     return true;
 }
 
 } // namespace WebCore