Remove toggle button code from Tab Strip.

ios/chrome/browser/ui/browser_view_controller.mm

 // 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.
 
 #import "ios/chrome/browser/ui/browser_view_controller.h"
 
 #import <AssetsLibrary/AssetsLibrary.h>
 #import <MobileCoreServices/MobileCoreServices.h>
 #import <PassKit/PassKit.h>
 #import <Photos/Photos.h>
@@ skipping 1711 matching lines @@
                           preloadProvider:_preloadController.get()]);
   [_toolbarController setTabCount:[_model count]];
   if (_voiceSearchController.get())
     _voiceSearchController->SetDelegate(_toolbarController);
 
   // If needed, create the tabstrip.
   if (IsIPadIdiom()) {
     _tabStripController.reset(
         [_dependencyFactory newTabStripControllerWithTabModel:_model]);
     _tabStripController.get().fullscreenDelegate = self;
-    [_tabStripController setHasTabSwitcherToggleSwitch:YES];
   }
 
   // Create infobar container.
   if (!_infoBarContainerDelegate) {
     _infoBarContainerDelegate.reset(new InfoBarContainerDelegateIOS(self));
     _infoBarContainer.reset(
         new InfoBarContainerIOS(_infoBarContainerDelegate.get()));
   }
 }
 
@@ skipping 3273 matching lines @@
 
 - (UIView*)voiceSearchButton {
   return _voiceSearchButton;
 }
 
 - (id<LogoAnimationControllerOwner>)logoAnimationControllerOwner {
   return [self currentLogoAnimationControllerOwner];
 }
 
 @end