Revert of Replace TabModel with WebStateList in GoogleLandingController.

ios/chrome/browser/ui/ntp/google_landing_mediator.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_CHROME_BROWSER_UI_NTP_GOOGLE_LANDING_MEDIATOR_H_
 #define IOS_CHROME_BROWSER_UI_NTP_GOOGLE_LANDING_MEDIATOR_H_
 
 #import <Foundation/Foundation.h>
 
 #import "ios/chrome/browser/ui/ntp/google_landing_data_source.h"
 
 @protocol GoogleLandingConsumer;
 @protocol OmniboxFocuser;
 @protocol UrlLoader;
-class WebStateList;
 
 namespace ios {
 class ChromeBrowserState;
 }
 
 // A mediator object that provides various data sources for google landing.
 @interface GoogleLandingMediator : NSObject<GoogleLandingDataSource>
 
 - (instancetype)initWithConsumer:(id<GoogleLandingConsumer>)consumer
                     browserState:(ios::ChromeBrowserState*)browserState
                           loader:(id<UrlLoader>)loader
                          focuser:(id<OmniboxFocuser>)focuser
               webToolbarDelegate:(id<WebToolbarDelegate>)webToolbarDelegate
-                    webStateList:(WebStateList*)webStateList
-    NS_DESIGNATED_INITIALIZER;
+                        tabModel:(TabModel*)tabModel NS_DESIGNATED_INITIALIZER;
 - (instancetype)init NS_UNAVAILABLE;
 
 // Get the maximum number of sites shown.
 + (NSUInteger)maxSitesShown;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_NTP_GOOGLE_LANDING_MEDIATOR_H_