Convert Pass()→std::move() for iOS build.

ios/chrome/browser/signin/signin_client_impl.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_client_impl.h"
 
 #include <stddef.h>
 
+#include <utility>
+
 #include "base/command_line.h"
 #include "base/guid.h"
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/content_settings/core/browser/cookie_settings.h"
 #include "components/keyed_service/core/service_access_type.h"
 #include "components/metrics/metrics_service.h"
 #include "components/signin/core/browser/profile_oauth2_token_service.h"
 #include "components/signin/core/browser/signin_cookie_changed_subscription.h"
@@ skipping 116 matching lines @@
 scoped_ptr<SigninClient::CookieChangedSubscription>
 SigninClientImpl::AddCookieChangedCallback(
     const GURL& url,
     const std::string& name,
     const net::CookieStore::CookieChangedCallback& callback) {
   scoped_refptr<net::URLRequestContextGetter> context_getter =
       browser_state_->GetRequestContext();
   DCHECK(context_getter.get());
   scoped_ptr<SigninCookieChangedSubscription> subscription(
       new SigninCookieChangedSubscription(context_getter, url, name, callback));
-  return subscription.Pass();
+  return std::move(subscription);
 }
 
 void SigninClientImpl::OnSignedIn(const std::string& account_id,
                                   const std::string& gaia_id,
                                   const std::string& username,
                                   const std::string& password) {
   ios::ChromeBrowserStateManager* browser_state_manager =
       GetApplicationContext()->GetChromeBrowserStateManager();
   BrowserStateInfoCache* cache =
       browser_state_manager->GetBrowserStateInfoCache();
@@ skipping 73 matching lines @@
     callback.Run();
   }
 }
 
 GaiaAuthFetcher* SigninClientImpl::CreateGaiaAuthFetcher(
     GaiaAuthConsumer* consumer,
     const std::string& source,
     net::URLRequestContextGetter* getter) {
   return new GaiaAuthFetcherIOS(consumer, source, getter, browser_state_);
 }