[ObjC ARC] Converts ios/chrome/browser/ui/ntp/recent_tabs:recent_tabs to ARC.

ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions_bridge.mm

 // 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.
 
 #import "ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions_bridge.h"
 
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/sync/driver/sync_service.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/signin/signin_manager_factory.h"
 #include "ios/chrome/browser/sync/ios_chrome_profile_sync_service_factory.h"
 #import "ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_table_view_controller.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace synced_sessions {
 
 #pragma mark - SyncedSessionsObserverBridge
 
 SyncedSessionsObserverBridge::SyncedSessionsObserverBridge(
     id<SyncedSessionsObserver> owner,
     ios::ChromeBrowserState* browserState)
     : SyncObserverBridge(
           owner,
           IOSChromeProfileSyncServiceFactory::GetForBrowserState(browserState)),
@@ skipping 41 matching lines @@
 #pragma mark - SigninManagerBase::Observer
 
 void SyncedSessionsObserverBridge::GoogleSignedOut(
     const std::string& account_id,
     const std::string& username) {
   first_sync_cycle_is_completed_ = false;
   [owner_ reloadSessions];
 }
 
 }  // namespace synced_sessions