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

ios/chrome/browser/signin/signin_manager_factory.h

 // 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.
 
 #ifndef IOS_CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_
 #define IOS_CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_
 
+#include <memory>
+
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
 
 namespace base {
 template <typename T>
 struct DefaultSingletonTraits;
 }  // namespace base
 
 class SigninManagerFactoryObserver;
 class SigninManager;
@@ skipping 35 matching lines @@
  private:
   friend struct base::DefaultSingletonTraits<SigninManagerFactory>;
 
   SigninManagerFactory();
   ~SigninManagerFactory() override;
 
   // List of observers. Checks that list is empty on destruction.
   mutable base::ObserverList<SigninManagerFactoryObserver, true> observer_list_;
 
   // BrowserStateKeyedServiceFactory:
-  scoped_ptr<KeyedService> BuildServiceInstanceFor(
+  std::unique_ptr<KeyedService> BuildServiceInstanceFor(
       web::BrowserState* context) const override;
   void BrowserStateShutdown(web::BrowserState* context) override;
 };
 }
 
 #endif  // IOS_CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_