Upstream Chrome on iOS source code [4/11].

ios/chrome/browser/ui/bookmarks/undo_manager_wrapper.h

+// 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.
+
+#ifndef IOS_CHROME_BROWSER_UI_BOOKMARKS_UNDO_MANAGER_WRAPPER_H_
+#define IOS_CHROME_BROWSER_UI_BOOKMARKS_UNDO_MANAGER_WRAPPER_H_
+
+#import <Foundation/Foundation.h>
+
+namespace ios {
+class ChromeBrowserState;
+}  // namespace ios
+
+// This object is a convenience ObjC wrapper around UndoManager.
+// On construction, it registers itself as an observer of the UndoManager.
+// On destruction, it unregisters itself as an observer of the UndoManager.
+// Provides a convenient interface to the UndoManager.
+// The general usage of this class should be:
+//  - startGroupingActions
+//  - *make changes to BookmarkModel*
+//  - stopGroupingActions
+//  - resetUndoManagerChanged
+// At a later point in time, an undo should only be attempted if
+// hasUndoManagerChanged returns NO.
+@interface UndoManagerWrapper : NSObject
+
+// Designated initializer.
+- (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState;
+
+// Subsequent changes to the BookmarkModel are grouped together so that a single
+// undo will revert all changes.
+- (void)startGroupingActions;
+// Stops grouping changes to the BookmarkModel. Calls to this method must mirror
+// calls to startGroupingActions.
+- (void)stopGroupingActions;
+
+// Resets the internal state for whether the UndoManager has changed to NO.
+- (void)resetUndoManagerChanged;
+// Returns YES if the UndoManager has changed since the last call to
+// resetUndoManagerChanged.
+- (BOOL)hasUndoManagerChanged;
+// Reverts the last change made to the BookmarkModel.
+- (void)undo;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_BOOKMARKS_UNDO_MANAGER_WRAPPER_H_