Make OAuth2TokenService and subclasses take delegate by unique_ptr

extensions/shell/browser/shell_oauth2_token_service.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_oauth2_token_service.h"
 
 #include "base/logging.h"
+#include "base/memory/ptr_util.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "extensions/shell/browser/shell_oauth2_token_service_delegate.h"
 
 namespace extensions {
 namespace {
 
 ShellOAuth2TokenService* g_instance = nullptr;
 
 }  // namespace
 
 ShellOAuth2TokenService::ShellOAuth2TokenService(
     content::BrowserContext* browser_context,
     std::string account_id,
     std::string refresh_token)
-    : OAuth2TokenService(new ShellOAuth2TokenServiceDelegate(browser_context,
-                                                             account_id,
-                                                             refresh_token)) {
+    : OAuth2TokenService(
+          base::MakeUnique<ShellOAuth2TokenServiceDelegate>(browser_context,
+                                                            account_id,
+                                                            refresh_token)) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   DCHECK(!g_instance);
   g_instance = this;
 }
 
 ShellOAuth2TokenService::~ShellOAuth2TokenService() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   DCHECK(g_instance);
   g_instance = nullptr;
 }
 
 // static
 ShellOAuth2TokenService* ShellOAuth2TokenService::GetInstance() {
   DCHECK(g_instance);
   return g_instance;
 }
 
 void ShellOAuth2TokenService::SetRefreshToken(
     const std::string& account_id,
     const std::string& refresh_token) {
   GetDelegate()->UpdateCredentials(account_id, refresh_token);
 }
 
 std::string ShellOAuth2TokenService::AccountId() const {
   return GetAccounts()[0];
 }
 
 }  // namespace extensions