Add a do_not_sync pref to ExtensionPrefs.

extensions/browser/extension_prefs.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 EXTENSIONS_BROWSER_EXTENSION_PREFS_H_
 #define EXTENSIONS_BROWSER_EXTENSION_PREFS_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 516 matching lines @@
   bool WasInstalledByDefault(const std::string& extension_id) const;
 
   // Returns true if the extension was installed as an oem app.
   bool WasInstalledByOem(const std::string& extension_id) const;
 
   // Helper method to acquire the installation time of an extension.
   // Returns base::Time() if the installation time could not be parsed or
   // found.
   base::Time GetInstallTime(const std::string& extension_id) const;
 
+  // Returns true if the extension should not be synced.
+  bool DoNotSync(const std::string& extension_id) const;
+
   // Gets/sets the last launch time of an extension.
   base::Time GetLastLaunchTime(const std::string& extension_id) const;
   void SetLastLaunchTime(const std::string& extension_id,
                          const base::Time& time);
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   bool extensions_disabled() const { return extensions_disabled_; }
 
   // The underlying PrefService.
@@ skipping 180 matching lines @@
   bool extensions_disabled_;
 
   ObserverList<ExtensionPrefsObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefs);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_PREFS_H_