[protector] Bump Preferences backup version to 3 to mitigate the startup prefs migration.

chrome/browser/protector/protector_service.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_PROTECTOR_PROTECTOR_SERVICE_H_
 #define CHROME_BROWSER_PROTECTOR_PROTECTOR_SERVICE_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 44 matching lines @@
   virtual void DiscardChange(BaseSettingChange* change, Browser* browser);
 
   // Opens a tab with specified URL in the browser window we've shown error
   // bubble for.
   virtual void OpenTab(const GURL& url, Browser* browser);
 
   // Returns the ProtectedPrefsWatcher instance for access to protected prefs
   // backup.
   ProtectedPrefsWatcher* GetPrefsWatcher();
 
+  // Stops observing pref changes and updating the backup. Should be used in
+  // tests only.
+  void StopWatchingPrefsForTesting();
+
   // Returns the most recent change instance or NULL if there are no changes.
   BaseSettingChange* GetLastChange();
 
   // Returns the Profile instance for this service.
   Profile* profile() { return profile_; }
 
  private:
   friend class ProtectorServiceTest;
 
   // Each item consists of an error and corresponding change instance.
@@ skipping 65 matching lines @@
 
   // Observes changes to protected prefs and updates the backup.
   scoped_ptr<ProtectedPrefsWatcher> prefs_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(ProtectorService);
 };
 
 }  // namespace protector
 
 #endif  // CHROME_BROWSER_PROTECTOR_PROTECTOR_SERVICE_H_