Refactor creation of SadTabView into a tab helper object

ios/web/public/test/fakes/test_web_state.mm

 // Copyright 2014 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/web/public/test/fakes/test_web_state.h"
 
 #include <stdint.h>
 
 #include "base/callback.h"
 #include "ios/web/public/web_state/web_state_observer.h"
@@ skipping 158 matching lines @@
     PageLoadCompletionStatus load_completion_status) {
   for (auto& observer : observers_)
     observer.PageLoaded(load_completion_status);
 }
 
 void TestWebState::OnProvisionalNavigationStarted(const GURL& url) {
   for (auto& observer : observers_)
     observer.ProvisionalNavigationStarted(url);
 }
 
+void TestWebState::OnRenderProcessGone() {
+  for (auto& observer : observers_)
+    observer.RenderProcessGone();
+}
+
+void TestWebState::ShowTransientContentView(CRWContentView* content_view) {}
+
 void TestWebState::SetCurrentURL(const GURL& url) {
   url_ = url;
 }
 
 void TestWebState::SetTrustLevel(URLVerificationTrustLevel trust_level) {
   trust_level_ = trust_level;
 }
 
 CRWWebViewProxyType TestWebState::GetWebViewProxy() const {
   return nullptr;
 }
 
 service_manager::InterfaceRegistry* TestWebState::GetMojoInterfaceRegistry() {
   return nullptr;
 }
 
 bool TestWebState::HasOpener() const {
   return false;
 }
 
 base::WeakPtr<WebState> TestWebState::AsWeakPtr() {
   NOTREACHED();
   return base::WeakPtr<WebState>();
 }
 
 }  // namespace web