cros: Fix crash when enabling arc in md-settings.

chrome/browser/ui/webui/settings/chromeos/device_stylus_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/settings/chromeos/device_stylus_handler.h"
 
 #include "ash/common/system/chromeos/palette/palette_utils.h"
 #include "base/bind.h"
 #include "chrome/browser/profiles/profile.h"
 #include "ui/events/devices/input_device_manager.h"
@@ skipping 48 matching lines @@
   note_taking_app_ids_.clear();
   base::ListValue apps_list;
 
   NoteTakingHelper* helper = NoteTakingHelper::Get();
   if (helper->android_enabled() && !helper->android_apps_received()) {
     // If Android is enabled but not ready yet, let the JS know so it can
     // disable the menu and display an explanatory message.
     waiting_for_android = true;
   } else {
     std::vector<NoteTakingAppInfo> available_apps =
-        NoteTakingHelper::Get()->GetAvailableApps(Profile::FromWebUI(web_ui()));
+        helper->GetAvailableApps(Profile::FromWebUI(web_ui()));
     for (const NoteTakingAppInfo& info : available_apps) {
       auto dict = base::MakeUnique<base::DictionaryValue>();
       dict->SetString(kAppNameKey, info.name);
       dict->SetString(kAppIdKey, info.app_id);
       dict->SetBoolean(kAppPreferredKey, info.preferred);
       apps_list.Append(std::move(dict));
 
       note_taking_app_ids_.insert(info.app_id);
     }
   }
 
+  AllowJavascript();
   CallJavascriptFunction(
       "cr.webUIListenerCallback", base::StringValue("onNoteTakingAppsUpdated"),
       apps_list, base::FundamentalValue(waiting_for_android));
 }
 
 void StylusHandler::RequestApps(const base::ListValue* unused_args) {
-  AllowJavascript();
   UpdateNoteTakingApps();
 }
 
 void StylusHandler::SetPreferredNoteTakingApp(const base::ListValue* args) {
   std::string app_id;
   CHECK(args->GetString(0, &app_id));
 
   // Sanity check: make sure that the ID we got back from WebUI is in the
   // currently-available set.
   if (!note_taking_app_ids_.count(app_id)) {
     LOG(ERROR) << "Got unknown note-taking-app ID \"" << app_id << "\"";
     return;
   }
 
   NoteTakingHelper::Get()->SetPreferredApp(Profile::FromWebUI(web_ui()),
                                            app_id);
 }
 
 void StylusHandler::HandleInitialize(const base::ListValue* args) {
-  AllowJavascript();
   if (ui::InputDeviceManager::GetInstance()->AreDeviceListsComplete())
     SendHasStylus();
 }
 
 void StylusHandler::SendHasStylus() {
   DCHECK(ui::InputDeviceManager::GetInstance()->AreDeviceListsComplete());
+  AllowJavascript();
   CallJavascriptFunction(
       "cr.webUIListenerCallback", base::StringValue("has-stylus-changed"),
       base::FundamentalValue(ash::palette_utils::HasStylusInput()));
 }
 
 }  // namespace settings
 }  // namespace chromeos