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

ios/clean/chrome/browser/ui/ntp/ntp_mediator.h

Index: ios/clean/chrome/browser/ui/ntp/ntp_mediator.h
diff --git a/ios/clean/chrome/browser/ui/ntp/ntp_mediator.h b/ios/clean/chrome/browser/ui/ntp/ntp_mediator.h
new file mode 100644
index 0000000000000000000000000000000000000000..210f0a3bf79010030e35ebb0df243ebe790009de
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+++ b/ios/clean/chrome/browser/ui/ntp/ntp_mediator.h
@@ -0,0 +1,20 @@
+// 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_MEDIATOR_H_
+#define IOS_CLEAN_CHROME_BROWSER_UI_NTP_NTP_MEDIATOR_H_
+
+#import <UIKit/UIKit.h>
+
+@protocol NTPConsumer;
+
+// A mediator object that sets an NTP view controller's appeareance based on
+// various data sources.
+@interface NTPMediator : NSObject
+- (instancetype)initWithConsumer:(id<NTPConsumer>)consumer
+    NS_DESIGNATED_INITIALIZER;
+- (instancetype)init NS_UNAVAILABLE;
+@end
+
+#endif  // IOS_CLEAN_CHROME_BROWSER_UI_NTP_NTP_MEDIATOR_H_