Removing iPad Tab Switcher experimental flag.

ios/chrome/browser/ui/main/browser_view_wrangler.mm

 // Copyright 2016 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/main/browser_view_wrangler.h"
 
 #include "base/mac/objc_property_releaser.h"
 #import "base/mac/scoped_nsobject.h"
 #include "ios/chrome/browser/application_context.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
@@ skipping 194 matching lines @@
     didChangeActiveTab:(Tab*)newTab
            previousTab:(Tab*)previousTab
                atIndex:(NSUInteger)index {
   [self updateDeviceSharingManager];
 }
 
 - (void)tabModel:(TabModel*)model didChangeTab:(Tab*)tab {
   [self updateDeviceSharingManager];
 }
 
-// Called when the number of tabs changes. Updates the switcher button
-// visibility in the various modes on tablet.
-- (void)tabModelDidChangeTabCount:(TabModel*)notifiedTabModel {
-  // If in tablet, update the mode switcher icon based on the number of tabs
-  // in the incognito tab strip. Doing this all the time simplifies a lot
-  // of the state transition logic and setting the property to the same value
-  // incurs no re-layout penalty.
-  [self updateModeToggle];
-}
-
 #pragma mark - Other public methods
 
 - (void)updateDeviceSharingManager {
   if (!self.deviceSharingManager) {
     self.deviceSharingManager =
         [[[DeviceSharingManager alloc] init] autorelease];
   }
   [self.deviceSharingManager updateBrowserState:_browserState];
 
   GURL activeURL;
@@ skipping 49 matching lines @@
   // be immediately deleted.
   self.otrTabModel = [self buildOtrTabModel:YES];
   DCHECK(![self.otrTabModel count]);
   DCHECK(_browserState->HasOffTheRecordChromeBrowserState());
 
   if (otrBVCIsCurrent) {
     _currentBVC = self.otrBVC;
   }
 }
 
-- (void)updateModeToggle {
-  if (IsIPadIdiom()) {
-    self.mainBVC.hasModeToggleSwitch = self.otrTabModel.count ? YES : NO;
-    self.otrBVC.hasModeToggleSwitch = YES;
-  }
-}
-
 #pragma mark - Internal methods
 
 - (TabModel*)buildOtrTabModel:(BOOL)empty {
   DCHECK(_browserState);
   // Ensure that the OTR ChromeBrowserState is created.
   ios::ChromeBrowserState* otrBrowserState =
       _browserState->GetOffTheRecordChromeBrowserState();
   DCHECK(otrBrowserState);
   return [self tabModelForBrowserState:otrBrowserState empty:empty];
 }
@@ skipping 27 matching lines @@
                                     tabModel:(TabModel*)tabModel {
   base::scoped_nsobject<BrowserViewControllerDependencyFactory> factory(
       [[BrowserViewControllerDependencyFactory alloc]
           initWithBrowserState:browserState]);
   return [[[BrowserViewController alloc] initWithTabModel:tabModel
                                              browserState:browserState
                                         dependencyFactory:factory] autorelease];
 }
 
 @end