[Payments] Add an entry for Payment Request to chrome://flags on iOS

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>
 #import <QuartzCore/QuartzCore.h>
 
 #include <stdint.h>
 #include <cmath>
 #include <memory>
 
 #include "base/base64.h"
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/files/file_path.h"
 #include "base/format_macros.h"
 #include "base/i18n/rtl.h"
 #include "base/ios/block_types.h"
 #include "base/ios/ios_util.h"
 #include "base/logging.h"
 #include "base/mac/bind_objc_block.h"
 #include "base/mac/bundle_locations.h"
 #include "base/mac/foundation_util.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "components/bookmarks/browser/base_bookmark_model_observer.h"
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h"
 #include "components/infobars/core/infobar_manager.h"
+#include "components/payments/core/features.h"
 #include "components/prefs/pref_service.h"
 #include "components/reading_list/core/reading_list_model.h"
 #include "components/search_engines/search_engines_pref_names.h"
 #include "components/search_engines/template_url_service.h"
 #include "components/sessions/core/tab_restore_service_helper.h"
 #include "components/strings/grit/components_strings.h"
 #include "components/toolbar/toolbar_model_impl.h"
 #include "ios/chrome/app/tests_hook.h"
 #include "ios/chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
@@ skipping 1778 matching lines @@
     _contextualSearchPanel = [self createPanelView];
     [self.view insertSubview:_contextualSearchPanel
                 aboveSubview:[_toolbarController view]];
     _contextualSearchController =
         [[ContextualSearchController alloc] initWithBrowserState:_browserState
                                                         delegate:self];
     [_contextualSearchController setPanel:_contextualSearchPanel];
     [_contextualSearchController setTab:[_model currentTab]];
   }
 
-  if (experimental_flags::IsPaymentRequestEnabled()) {
+  if (base::FeatureList::IsEnabled(payments::features::kWebPayments)) {
     _paymentRequestManager = [[PaymentRequestManager alloc]
         initWithBaseViewController:self
                       browserState:_browserState];
     [_paymentRequestManager setToolbarModel:_toolbarModelIOS.get()];
     [_paymentRequestManager setWebState:[_model currentTab].webState];
   }
 }
 
 // Set the frame for the various views. View must be loaded.
 - (void)setUpViewLayout {
@@ skipping 3379 matching lines @@
 
 - (UIView*)voiceSearchButton {
   return _voiceSearchButton;
 }
 
 - (id<LogoAnimationControllerOwner>)logoAnimationControllerOwner {
   return [self currentLogoAnimationControllerOwner];
 }
 
 @end