Remove the iOS QR Code scanner experiment code.

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 4101 matching lines @@
       [self showReadingList];
       break;
     case IDC_VOICE_SEARCH:
       // If the voice search command is coming from a UIView sender, store it
       // before sending the command up the responder chain.
       if ([sender isKindOfClass:[UIView class]])
         _voiceSearchButton.reset(sender);
       [super chromeExecuteCommand:sender];
       break;
     case IDC_SHOW_QR_SCANNER:
-      if (experimental_flags::IsQRCodeReaderEnabled()) {
-        [self showQRScanner];
-      }
+      [self showQRScanner];
       break;
     case IDC_SHOW_SUGGESTIONS:
       if (experimental_flags::IsSuggestionsUIEnabled()) {
         [self showSuggestionsUI];
       }
       break;
     default:
       // Unknown commands get sent up the responder chain.
       [super chromeExecuteCommand:sender];
       break;
@@ skipping 1034 matching lines @@
 
 - (UIView*)voiceSearchButton {
   return _voiceSearchButton;
 }
 
 - (id<LogoAnimationControllerOwner>)logoAnimationControllerOwner {
   return [self currentLogoAnimationControllerOwner];
 }
 
 @end