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

ios/public/provider/chrome/browser/chrome_browser_provider.mm

 // Copyright 2013 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/public/provider/chrome/browser/chrome_browser_provider.h"
 
 #include <cstddef>
 
 #include "base/logging.h"
 #include "components/metrics/metrics_provider.h"
@@ skipping 88 matching lines @@
     const std::vector<int>& desired_sizes_in_pixel,
     const favicon_base::FaviconResultsCallback& callback) const {}
 
 bool ChromeBrowserProvider::IsSafeBrowsingEnabled(
     const base::Closure& on_update_callback) {
   return false;
 }
 
 void ChromeBrowserProvider::OnMetricsServicesManagerClientDestroyed() {}
 
-scoped_ptr<browser_sync::SyncedWindowDelegatesGetter>
+std::unique_ptr<browser_sync::SyncedWindowDelegatesGetter>
 ChromeBrowserProvider::CreateSyncedWindowDelegatesGetter(
     ios::ChromeBrowserState* browser_state) {
   return nullptr;
 }
 
 net::URLRequestContextGetter*
 ChromeBrowserProvider::GetSafeBrowsingURLRequestContext() {
   return nullptr;
 }
 
 }  // namespace ios