Allocate SocketController lazily.

chrome/browser/extensions/extension_service.h

 // Copyright (c) 2011 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_
 #pragma once
 
 #include <list>
 #include <map>
@@ skipping 556 matching lines @@
 #if defined(UNIT_TEST)
   void TrackTerminatedExtensionForTest(const Extension* extension) {
     TrackTerminatedExtension(extension);
   }
 #endif
 
   ExtensionWarningSet* extension_warnings() {
     return &extension_warnings_;
   }
 
-  extensions::SocketController* socket_controller() {
-    return socket_controller_;
-  }
+  // Call only from IO thread.
+  extensions::SocketController* socket_controller();
 
   // Implement ImageLoadingTracker::Observer. |tracker_| is used to
   // load the application's icon, which is done when we start creating an
   // application's shortcuts. This method receives the icon, and completes
   // the process of installing the shortcuts.
   virtual void OnImageLoaded(SkBitmap* image,
                              const ExtensionResource& resource,
                              int index) OVERRIDE;
  private:
   // Bundle of type (app or extension)-specific sync stuff.
@@ skipping 260 matching lines @@
   ImageLoadingTracker tracker_;
 
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            InstallAppsWithUnlimtedStorage);
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            InstallAppsAndCheckStorageProtection);
   DISALLOW_COPY_AND_ASSIGN(ExtensionService);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_