Add shutdown notification and service refs to SyncServiceObserver.

chrome/browser/extensions/external_pref_loader.h

 // Copyright (c) 2012 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_EXTERNAL_PREF_LOADER_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTERNAL_PREF_LOADER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 57 matching lines @@
 
   const Options options_;
 
  private:
   friend class base::RefCountedThreadSafe<ExternalLoader>;
 
   // sync_preferences::PrefServiceSyncableObserver:
   void OnIsSyncingChanged() override;
 
   // syncer::SyncServiceObserver
-  void OnStateChanged() override;
+  void OnStateChanged(syncer::SyncService* sync) override;
 
   // If priority sync ready posts LoadOnFileThread and return true.
   bool PostLoadIfPrioritySyncReady();
 
   // Post LoadOnFileThread and stop observing for sync service states.
   void PostLoadAndRemoveObservers();
 
   // Actually searches for and loads candidate standalone extension preference
   // files in the path corresponding to |base_path_id|.
   // Must be called on the file thread.
@@ skipping 47 matching lines @@
 
   base::FilePath fake_base_path_;
   std::unique_ptr<base::DictionaryValue> testing_prefs_;
 
   DISALLOW_COPY_AND_ASSIGN(ExternalTestingLoader);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTERNAL_PREF_LOADER_H_