Return unique_ptr from WebClient::CreateWebMainParts()

ios/chrome/browser/web/chrome_web_client.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/chrome/browser/web/chrome_web_client.h"
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/ios/ios_util.h"
 #include "base/mac/bundle_locations.h"
+#include "base/memory/ptr_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/dom_distiller/core/url_constants.h"
 #include "components/prefs/pref_service.h"
 #include "components/strings/grit/components_strings.h"
 #include "components/task_scheduler_util/browser/initialization.h"
 #include "components/version_info/version_info.h"
 #include "ios/chrome/browser/application_context.h"
 #include "ios/chrome/browser/browser_about_rewriter.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/chrome_switches.h"
@@ skipping 31 matching lines @@
                  << base::SysNSStringToUTF8(error.description);
   DCHECK(content);
   return content;
 }
 }
 
 ChromeWebClient::ChromeWebClient() {}
 
 ChromeWebClient::~ChromeWebClient() {}
 
-web::WebMainParts* ChromeWebClient::CreateWebMainParts() {
-  return new IOSChromeMainParts(*base::CommandLine::ForCurrentProcess());
+std::unique_ptr<web::WebMainParts> ChromeWebClient::CreateWebMainParts() {
+  return base::MakeUnique<IOSChromeMainParts>(
+      *base::CommandLine::ForCurrentProcess());
 }
 
 void ChromeWebClient::PreWebViewCreation() const {
   // Initialize the audio session to allow a web page's audio to continue
   // playing after the app is backgrounded.
   VoiceSearchProvider* voice_provider =
       ios::GetChromeBrowserProvider()->GetVoiceSearchProvider();
   if (voice_provider) {
     AudioSessionController* audio_controller =
         voice_provider->GetAudioSessionController();
@@ skipping 104 matching lines @@
   // If this call fails, web will fall back to the default params.
   *params_vector =
       task_scheduler_util::GetBrowserWorkerPoolParamsFromVariations();
   *index_to_traits_callback =
       base::Bind(&task_scheduler_util::BrowserWorkerPoolIndexForTraits);
 }
 
 void ChromeWebClient::PerformExperimentalTaskSchedulerRedirections() {
   task_scheduler_util::MaybePerformBrowserTaskSchedulerRedirection();
 }