Convert //ios from scoped_ptr to std::unique_ptr.

ios/chrome/browser/signin/signin_manager_factory.cc

 // Copyright 2015 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 "ios/chrome/browser/signin/signin_manager_factory.h"
 
 #include <utility>
 
 #include "base/memory/singleton.h"
 #include "base/time/time.h"
@@ skipping 61 matching lines @@
     SigninManagerFactoryObserver* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
 void SigninManagerFactory::NotifyObserversOfSigninManagerCreationForTesting(
     SigninManager* manager) {
   FOR_EACH_OBSERVER(SigninManagerFactoryObserver, observer_list_,
                     SigninManagerCreated(manager));
 }
 
-scoped_ptr<KeyedService> SigninManagerFactory::BuildServiceInstanceFor(
+std::unique_ptr<KeyedService> SigninManagerFactory::BuildServiceInstanceFor(
     web::BrowserState* context) const {
   ios::ChromeBrowserState* chrome_browser_state =
       ios::ChromeBrowserState::FromBrowserState(context);
-  scoped_ptr<SigninManager> service(new SigninManager(
+  std::unique_ptr<SigninManager> service(new SigninManager(
       SigninClientFactory::GetForBrowserState(chrome_browser_state),
       OAuth2TokenServiceFactory::GetForBrowserState(chrome_browser_state),
       ios::AccountTrackerServiceFactory::GetForBrowserState(
           chrome_browser_state),
       ios::GaiaCookieManagerServiceFactory::GetForBrowserState(
           chrome_browser_state)));
   service->Initialize(GetApplicationContext()->GetLocalState());
   FOR_EACH_OBSERVER(SigninManagerFactoryObserver, observer_list_,
                     SigninManagerCreated(service.get()));
   return std::move(service);
 }
 
 void SigninManagerFactory::BrowserStateShutdown(web::BrowserState* context) {
   SigninManager* manager =
       static_cast<SigninManager*>(GetServiceForBrowserState(context, false));
   if (manager)
     FOR_EACH_OBSERVER(SigninManagerFactoryObserver, observer_list_,
                       SigninManagerShutdown(manager));
   BrowserStateKeyedServiceFactory::BrowserStateShutdown(context);
 }
 
 }  // namespace ios