Skip enhanced bookmarks cluster requests if it's not being used.

components/enhanced_bookmarks/bookmark_server_service.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 COMPONENTS_ENHANCED_BOOKMARKS_BOOKMARK_SERVER_SERVICE_H_
 #define COMPONENTS_ENHANCED_BOOKMARKS_BOOKMARK_SERVER_SERVICE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 29 matching lines @@
                               private OAuth2TokenService::Consumer,
                               public EnhancedBookmarkModelObserver {
  public:
   BookmarkServerService(
       scoped_refptr<net::URLRequestContextGetter> request_context_getter,
       ProfileOAuth2TokenService* token_service,
       SigninManagerBase* signin_manager,
       EnhancedBookmarkModel* enhanced_bookmark_model);
   virtual ~BookmarkServerService();
 
-  void AddObserver(BookmarkServerServiceObserver* observer);
+  virtual void AddObserver(BookmarkServerServiceObserver* observer);
   void RemoveObserver(BookmarkServerServiceObserver* observer);
+  bool MightHaveObservers();

[danduong, 2014/10/20 18:45:38]

Any reason we don't just expose observers as protected?

[Kibeom Kim (inactive), 2014/10/20 20:05:47]

Done.

 
  protected:
   // Retrieves a bookmark by using its remote id. Returns null if nothing
   // matches.
   virtual const BookmarkNode* BookmarkForRemoteId(
       const std::string& remote_id) const;
   const std::string RemoteIDForBookmark(const BookmarkNode* bookmark) const;
 
   // Notifies the observers that something changed.
   void Notify();
@@ skipping 49 matching lines @@
   // To have access to the right context getter for the profile.
   scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
   // The fetcher used to query the server.
   scoped_ptr<net::URLFetcher> url_fetcher_;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkServerService);
 };
 }  // namespace enhanced_bookmarks
 
 #endif  // COMPONENTS_ENHANCED_BOOKMARKS_BOOKMARK_SERVER_SERVICE_H_