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

ios/chrome/browser/ui/bookmarks/undo_manager_wrapper.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/ui/bookmarks/undo_manager_wrapper.h"
 
 #include <memory>
 
 #include "components/undo/bookmark_undo_service.h"
 #include "components/undo/undo_manager.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/ui/bookmarks/undo_manager_bridge_observer.h"
 #include "ios/chrome/browser/undo/bookmark_undo_service_factory.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @interface UndoManagerWrapper ()<UndoManagerBridgeObserver> {
   std::unique_ptr<bookmarks::UndoManagerBridge> _bridge;
 }
 @property(nonatomic, assign) UndoManager* undoManager;
 @property(nonatomic, assign) BOOL hasUndoManagerChanged;
 @end
 
 @implementation UndoManagerWrapper
 @synthesize hasUndoManagerChanged = _hasUndoManagerChanged;
 @synthesize undoManager = _undoManager;
@@ skipping 10 matching lines @@
         ios::BookmarkUndoServiceFactory::GetForBrowserState(browserState)
             ->undo_manager();
     _bridge.reset(new bookmarks::UndoManagerBridge(self));
     _undoManager->AddObserver(_bridge.get());
   }
   return self;
 }
 
 - (void)dealloc {
   _undoManager->RemoveObserver(_bridge.get());
-  [super dealloc];
 }
 
 #pragma mark - Public Methods
 
 - (void)startGroupingActions {
   self.undoManager->StartGroupingActions();
 }
 
 - (void)stopGroupingActions {
   self.undoManager->EndGroupingActions();
 }
 
 - (void)resetUndoManagerChanged {
   self.hasUndoManagerChanged = NO;
 }
 
 - (void)undo {
   self.undoManager->Undo();
 }
 
 #pragma mark - UndoManagerBridgeObserver
 
 - (void)undoManagerChanged {
   self.hasUndoManagerChanged = YES;
 }
 
 @end