[ios clean] Add placeholder for NTP bookmarks, chrome home and open tabs.

ios/clean/chrome/browser/ui/ntp/ntp_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_NTP_NTP_VIEW_CONTROLLER_H_
+#define IOS_CLEAN_CHROME_BROWSER_UI_NTP_NTP_VIEW_CONTROLLER_H_
+
+#import <UIKit/UIKit.h>
+
+#import "ios/clean/chrome/browser/ui/ntp/ntp_consumer.h"
+
+@protocol NTPCommands;
+
+// View controller that displays a new tab page.
+@interface NTPViewController : UIViewController<NTPConsumer>
+
+// The dispatcher for this view controller
+@property(nonatomic, weak) id<NTPCommands> dispatcher;
+
+// Setting this property adds a Chrome Home panel.
+@property(nonatomic, strong) UIViewController* homeViewController;
+
+// Setting this property adds a bookmarks panel on iPad or present a bookmarks
+// panel on iPhone.
+@property(nonatomic, strong) UIViewController* bookmarksViewController;
+
+// Setting this property adds a recent tabs panel on iPad or present a bookmarks
+// panel on iPhone.
+@property(nonatomic, strong) UIViewController* recentTabsViewController;
+@end
+
+#endif  // IOS_CLEAN_CHROME_BROWSER_UI_NTP_NTP_VIEW_CONTROLLER_H_