Fix crash in SyncSetupWizard::IsVisible()

chrome/browser/ui/webui/sync_setup_handler.cc

 // Copyright (c) 2011 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/sync_setup_handler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
@@ skipping 697 matching lines @@
   }
 
   ShowSetupUI();
 }
 
 // Private member functions.
 
 bool SyncSetupHandler::FocusExistingWizard() {
   Profile* profile = Profile::FromWebUI(web_ui_);
   ProfileSyncService* service = profile->GetProfileSyncService();
-  DCHECK(service);
+  if (!service)
+    return false;
+
   // If the wizard is already visible, focus it.
   if (service->get_wizard().IsVisible()) {
     service->get_wizard().Focus();
     return true;
   }
   return false;
 }
 
 void SyncSetupHandler::CloseOverlay() {
   web_ui_->CallJavascriptFunction("OptionsPage.closeOverlay");
@@ skipping 27 matching lines @@
 }
 
 void SyncSetupHandler::ShowLoginErrorMessage(const string16& error_message) {
   DictionaryValue args;
   Profile* profile = Profile::FromWebUI(web_ui_);
   ProfileSyncService* service = profile->GetProfileSyncService();
   SyncSetupFlow::GetArgsForGaiaLogin(service, &args);
   args.SetString("error_message", error_message);
   ShowGaiaLogin(args);
 }