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

ios/web/app/web_main_loop.mm

 // 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 "ios/web/app/web_main_loop.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 64 matching lines @@
   }
   base::MessageLoopForUI::current()->Attach();
 
   InitializeMainThread();
 
 #if 0
   // TODO(crbug.com/228014): SystemMonitor is not working properly on iOS.
   system_monitor_.reset(new base::SystemMonitor);
 #endif
   // TODO(rohitrao): Do we need PowerMonitor on iOS, or can we get rid of it?
-  scoped_ptr<base::PowerMonitorSource> power_monitor_source(
+  std::unique_ptr<base::PowerMonitorSource> power_monitor_source(
       new base::PowerMonitorDeviceSource());
   power_monitor_.reset(new base::PowerMonitor(std::move(power_monitor_source)));
   network_change_notifier_.reset(net::NetworkChangeNotifier::Create());
 
   if (parts_) {
     parts_->PostMainMessageLoopStart();
   }
 }
 
 void WebMainLoop::CreateStartupTasks() {
@@ skipping 27 matching lines @@
   base::Thread::Options io_message_loop_options;
   io_message_loop_options.message_loop_type = base::MessageLoop::TYPE_IO;
 
   // Start threads in the order they occur in the WebThread::ID
   // enumeration, except for WebThread::UI which is the main
   // thread.
   //
   // Must be size_t so we can increment it.
   for (size_t thread_id = WebThread::UI + 1; thread_id < WebThread::ID_COUNT;
        ++thread_id) {
-    scoped_ptr<WebThreadImpl>* thread_to_start = nullptr;
+    std::unique_ptr<WebThreadImpl>* thread_to_start = nullptr;
     base::Thread::Options options;
 
     switch (thread_id) {
       // TODO(rohitrao): We probably do not need all of these threads.  Remove
       // the ones that serve no purpose.  http://crbug.com/365909
       case WebThread::DB:
         thread_to_start = &db_thread_;
         options.timer_slack = base::TIMER_SLACK_MAXIMUM;
         break;
       case WebThread::FILE_USER_BLOCKING:
@@ skipping 129 matching lines @@
   main_thread_.reset(
       new WebThreadImpl(WebThread::UI, base::MessageLoop::current()));
 }
 
 int WebMainLoop::WebThreadsStarted() {
   cookie_notification_bridge_.reset(new CookieNotificationBridge);
   return result_code_;
 }
 
 }  // namespace web