Convert TabModelTest to use the public API of TabModel.

ios/chrome/browser/tabs/tab_model.h

 // Copyright 2012 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_TABS_TAB_MODEL_H_
 #define IOS_CHROME_BROWSER_TABS_TAB_MODEL_H_
 
 #import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>
 
@@ skipping 266 matching lines @@
 - (void)browserStateDestroyed;
 // Called by the Tab to inform its parent that it has been closed.
 - (void)didCloseTab:(Tab*)closedTab;
 // Called by |tab| to inform the model that a navigation has taken place.
 // TODO(crbug.com/661983): once more of the navigation state has moved into WC,
 // replace this with WebStateObserver.
 - (void)navigationCommittedInTab:(Tab*)tab;
 
 @end
 
-@interface TabModel (PrivateForTestingOnly)
-
-// Opens a tab at the specified URL. The newly created tab will not be the child
-// of any other tab. This does not go through the order controller. Used a page
-// transition of TYPED.
-- (Tab*)addTabWithURL:(const GURL&)URL referrer:(const web::Referrer&)referrer;
-
-// Inserts a new tab at the given |index| with the given |URL| and |referrer|.
-// This does not go through the order controller. Uses a page transition of
-// TYPED.
-- (Tab*)insertTabWithURL:(const GURL&)URL
-                referrer:(const web::Referrer&)referrer
-                  opener:(Tab*)parentTab
-                 atIndex:(NSUInteger)index;
-
-@end
-
 #endif  // IOS_CHROME_BROWSER_TABS_TAB_MODEL_H_