[ios] ARCMigrate i/c/b/tabs/tab_model_synced_window_delegate*.

ios/chrome/browser/tabs/tab_model_synced_window_delegate_getter.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.
 
 #include "ios/chrome/browser/tabs/tab_model_synced_window_delegate_getter.h"
 
 #include "base/logging.h"
 #include "ios/chrome/browser/application_context.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state_manager.h"
 #import "ios/chrome/browser/tabs/tab_model.h"
 #import "ios/chrome/browser/tabs/tab_model_list.h"
 #import "ios/chrome/browser/tabs/tab_model_synced_window_delegate.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 TabModelSyncedWindowDelegatesGetter::TabModelSyncedWindowDelegatesGetter() {}
 
 TabModelSyncedWindowDelegatesGetter::~TabModelSyncedWindowDelegatesGetter() {}
 
 TabModelSyncedWindowDelegatesGetter::SyncedWindowDelegateMap
 TabModelSyncedWindowDelegatesGetter::GetSyncedWindowDelegates() {
   SyncedWindowDelegateMap synced_window_delegates;
 
   std::vector<ios::ChromeBrowserState*> browser_states =
       GetApplicationContext()
@@ skipping 18 matching lines @@
 }
 
 const sync_sessions::SyncedWindowDelegate*
 TabModelSyncedWindowDelegatesGetter::FindById(SessionID::id_type session_id) {
   for (const auto& iter : GetSyncedWindowDelegates()) {
     if (session_id == iter.second->GetSessionId())
       return iter.second;
   }
   return nullptr;
 }