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

extensions/shell/browser/shell_extension_system.cc

 // 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.
 
 #include "extensions/shell/browser/shell_extension_system.h"
 
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ skipping 158 matching lines @@
 
 ContentVerifier* ShellExtensionSystem::content_verifier() {
   return nullptr;
 }
 
 scoped_ptr<ExtensionSet> ShellExtensionSystem::GetDependentExtensions(
     const Extension* extension) {
   return make_scoped_ptr(new ExtensionSet());
 }
 
+void ShellExtensionSystem::InstallUpdate(const std::string& extension_id,
+                                         const base::FilePath& temp_dir) {
+  NOTREACHED();
+  base::DeleteFile(temp_dir, true /* recursive */);
+}
+
 void ShellExtensionSystem::OnExtensionRegisteredWithRequestContexts(
     scoped_refptr<Extension> extension) {
   ExtensionRegistry* registry = ExtensionRegistry::Get(browser_context_);
   registry->AddReady(extension);
   registry->TriggerOnReady(extension.get());
 }
 
 }  // namespace extensions