Fixed crash when looking for iframe when gaia is being hosted in webview

chrome/browser/ui/webui/signin/inline_login_ui.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/ui/webui/signin/inline_login_ui.h"
 
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/extensions/tab_helper.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/chromium_strings.h"
 #include "components/signin/core/common/profile_management_switches.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/browser/web_ui_data_source.h"
 #include "extensions/browser/guest_view/guest_view_manager.h"
 #include "grit/browser_resources.h"
 #if defined(OS_CHROMEOS)
+#include "chrome/browser/chromeos/login/startup_utils.h"
 #include "chrome/browser/ui/webui/chromeos/login/inline_login_handler_chromeos.h"
 #else
 #include "chrome/browser/ui/webui/signin/inline_login_handler_impl.h"
 #endif
 
 namespace {
 
 content::WebUIDataSource* CreateWebUIDataSource() {
   content::WebUIDataSource* source =
         content::WebUIDataSource::Create(chrome::kChromeUIChromeSigninHost);
@@ skipping 58 matching lines @@
 }
 
 InlineLoginUI::~InlineLoginUI() {}
 
 // Gets the Gaia iframe within a WebContents.
 content::RenderFrameHost* InlineLoginUI::GetAuthIframe(
     content::WebContents* web_contents,
     const GURL& parent_origin,
     const std::string& parent_frame_name) {
   std::set<content::RenderFrameHost*> frame_set;
-  if (switches::IsEnableWebviewBasedSignin()) {
+  bool is_webview = switches::IsEnableWebviewBasedSignin();
+#if defined(OS_CHROMEOS)
+  is_webview = is_webview || chromeos::StartupUtils::IsWebviewSigninEnabled();
+#endif
+  if (is_webview) {
     extensions::GuestViewManager* manager =
         extensions::GuestViewManager::FromBrowserContext(
             web_contents->GetBrowserContext());
     manager->ForEachGuest(web_contents,
                           base::Bind(&AddToSetIfSigninWebview, &frame_set));
   } else {
     web_contents->ForEachFrame(
         base::Bind(&AddToSetIfIsAuthIframe, &frame_set,
                    parent_origin, parent_frame_name));
   }
   DCHECK_GE(1U, frame_set.size());
   if (!frame_set.empty())
     return *frame_set.begin();
 
   return NULL;
 }