[iOS Clean] Added dialogs UI support.

ios/clean/chrome/browser/ui/dialogs/dialog_view_controller.h

+// Copyright 2017 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_CLEAN_CHROME_BROWSER_UI_DIALOGS_DIALOG_VIEW_CONTROLLER_H_
+#define IOS_CLEAN_CHROME_BROWSER_UI_DIALOGS_DIALOG_VIEW_CONTROLLER_H_
+
+#import <UIKit/UIKit.h>
+
+#import "ios/clean/chrome/browser/ui/dialogs/dialog_consumer.h"
+
+@protocol DialogDismissalCommands;
+
+// Class used to display dialogs.  It is configured through the DialogConsumer
+// protocol, and is not meant to be subclassed.
+@interface DialogViewController : UIAlertController<DialogConsumer>
+
+// Initializer for a dialog with |style| that uses |dispatcher| to manage its
+// dismissal.
+- (instancetype)initWithStyle:(UIAlertControllerStyle)style
+                   dispatcher:(id<DialogDismissalCommands>)dispatcher;
+
+@end
+
+#endif  // IOS_CLEAN_CHROME_BROWSER_UI_DIALOGS_DIALOG_VIEW_CONTROLLER_H_