Add extensions code to use common updater in components/update_client/

extensions/browser/mock_extension_system.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_MOCK_EXTENSION_SYSTEM_H_
 #define EXTENSIONS_BROWSER_MOCK_EXTENSION_SYSTEM_H_
 
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "extensions/browser/extension_registry_factory.h"
 #include "extensions/browser/extension_system.h"
@@ skipping 23 matching lines @@
   SharedUserScriptMaster* shared_user_script_master() override;
   StateStore* state_store() override;
   StateStore* rules_store() override;
   InfoMap* info_map() override;
   QuotaService* quota_service() override;
   AppSorting* app_sorting() override;
   const OneShotEvent& ready() const override;
   ContentVerifier* content_verifier() override;
   scoped_ptr<ExtensionSet> GetDependentExtensions(
       const Extension* extension) override;
+  void InstallUpdate(const std::string& extension_id,
+                     const base::FilePath& temp_dir) override;
 
  private:
   content::BrowserContext* browser_context_;
   OneShotEvent ready_;
 
   DISALLOW_COPY_AND_ASSIGN(MockExtensionSystem);
 };
 
 // A factory to create a MockExtensionSystem. Sample use:
 //
@@ skipping 24 matching lines @@
         GetServiceForBrowserContext(context, true));
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockExtensionSystemFactory);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_MOCK_EXTENSION_SYSTEM_H_