Issue 4722 - Remove old check for Chrome notification API

lib/notificationHelper.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 14 matching lines @@
 let {Prefs} = require("prefs");
 
 let activeNotification = null;
 let activeButtons = null;
 let defaultDisplayMethods = ["popup"];
 let displayMethods = Object.create(null);
 displayMethods.critical = ["icon", "notification", "popup"];
 displayMethods.question = ["notification"];
 displayMethods.normal = ["notification"];
 displayMethods.information = ["icon", "popup"];
-
-let canUseChromeNotifications = typeof chrome != "undefined" && "notifications" in chrome;
 
 function prepareNotificationIconAndPopup()
 {
   let animateIcon = shouldDisplay("icon", activeNotification.type);
   activeNotification.onClicked = function()
   {
     if (animateIcon)
       stopIconAnimation();
     notificationClosed();
   };
@@ skipping 128 matching lines @@
 
   activeNotification = notification;
   if (shouldDisplay("notification", activeNotification.type))
   {
     let texts = NotificationStorage.getLocalizedTexts(notification);
     let title = texts.title || "";
     let message = texts.message ? texts.message.replace(/<\/?(a|strong)>/g, "") : "";
     let iconUrl = ext.getURL("icons/detailed/abp-128.png");
     let linkCount = (activeNotification.links || []).length;
 
-    if (canUseChromeNotifications)
+    if ("notifications" in chrome)
     {
       activeButtons = getNotificationButtons(activeNotification.type, texts.message);
       chrome.notifications.create("", {
         type: "basic",
         title: title,
         iconUrl: iconUrl,
         message: message,
         buttons: activeButtons.map(button => ({title: button.title})),
         priority: 2 // We use the highest priority to prevent the notification from closing automatically
       });
@@ skipping 30 matching lines @@
     }
   }
   prepareNotificationIconAndPopup();
 };
 
 /**
  * Initializes the notification system.
  */
 exports.initNotifications = function()
 {
-  if (canUseChromeNotifications)
+  if ("notifications" in chrome)
     initChromeNotifications();
   initAntiAdblockNotification();
 };
 
 /**
  * Gets the active notification to be shown if any.
  *
  * @return {?object}
  */
 exports.getActiveNotification = function()
@@ skipping 15 matching lines @@
   let methods = displayMethods[notificationType] || defaultDisplayMethods;
   return methods.indexOf(method) > -1;
 };
 
 ext.pages.onLoading.addListener(page =>
 {
   NotificationStorage.showNext(stringifyURL(page.url));
 });
 
 NotificationStorage.addShowListener(showNotification);