Refactor creation of SadTabView into a tab helper object

ios/chrome/browser/tabs/tab_helper_util.mm

 // Copyright 2017 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/tabs/tab_helper_util.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
@@ skipping 15 matching lines @@
 #import "ios/chrome/browser/signin/account_consistency_service_factory.h"
 #import "ios/chrome/browser/ssl/ios_security_state_tab_helper.h"
 #import "ios/chrome/browser/store_kit/store_kit_tab_helper.h"
 #import "ios/chrome/browser/sync/ios_chrome_synced_tab_delegate.h"
 #import "ios/chrome/browser/tabs/legacy_tab_helper.h"
 #import "ios/chrome/browser/tabs/tab.h"
 #import "ios/chrome/browser/translate/chrome_ios_translate_client.h"
 #import "ios/chrome/browser/web/blocked_popup_tab_helper.h"
 #import "ios/chrome/browser/web/network_activity_indicator_tab_helper.h"
 #import "ios/chrome/browser/web/repost_form_tab_helper.h"
+#import "ios/chrome/browser/web/sad_tab_tab_helper.h"
 #import "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #import "ios/web/public/web_state/web_state.h"
 
 void AttachTabHelpers(web::WebState* web_state) {
   Tab* tab = LegacyTabHelper::GetTabForWebState(web_state);
 
   ios::ChromeBrowserState* browser_state =
       ios::ChromeBrowserState::FromBrowserState(web_state->GetBrowserState());
 
   // IOSChromeSessionTabHelper comes first because it sets up the tab ID,
   // and other helpers may rely on that.
   IOSChromeSessionTabHelper::CreateForWebState(web_state);
 
   NetworkActivityIndicatorTabHelper::CreateForWebState(web_state, tab.tabId);
   IOSChromeSyncedTabDelegate::CreateForWebState(web_state);
   InfoBarManagerImpl::CreateForWebState(web_state);
   IOSSecurityStateTabHelper::CreateForWebState(web_state);
   RepostFormTabHelper::CreateForWebState(web_state);
   BlockedPopupTabHelper::CreateForWebState(web_state);
   FindTabHelper::CreateForWebState(web_state, tab.findInPageControllerDelegate);
   StoreKitTabHelper::CreateForWebState(web_state);
+  SadTabTabHelper::CreateForWebState(web_state, tab);
 
   ReadingListModel* model =
       ReadingListModelFactory::GetForBrowserState(browser_state);
   ReadingListWebStateObserver::FromWebState(web_state, model);
 
   if (AccountConsistencyService* account_consistency_service =
           ios::AccountConsistencyServiceFactory::GetForBrowserState(
               browser_state)) {
     account_consistency_service->SetWebStateHandler(web_state, tab);
   }
   ChromeIOSTranslateClient::CreateForWebState(web_state);
 
   ios::ChromeBrowserState* original_browser_state =
       browser_state->GetOriginalChromeBrowserState();
   favicon::WebFaviconDriver::CreateForWebState(
       web_state,
       ios::FaviconServiceFactory::GetForBrowserState(
           original_browser_state, ServiceAccessType::IMPLICIT_ACCESS),
       ios::HistoryServiceFactory::GetForBrowserState(
           original_browser_state, ServiceAccessType::IMPLICIT_ACCESS),
       ios::BookmarkModelFactory::GetForBrowserState(original_browser_state));
   history::WebStateTopSitesObserver::CreateForWebState(
       web_state,
       ios::TopSitesFactory::GetForBrowserState(original_browser_state).get());
 
   // Allow the embedder to attach tab helpers.
   ios::GetChromeBrowserProvider()->AttachTabHelpers(web_state, tab);
 }