Issue 5028 - Use browser namespace

ext/devtools.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 "use strict";
 
 (function()
 {
-  let inspectedTabId = chrome.devtools.inspectedWindow.tabId;
-  let port = chrome.runtime.connect({name: "devtools-" + inspectedTabId});
+  let inspectedTabId = browser.devtools.inspectedWindow.tabId;
+  let port = browser.runtime.connect({name: "devtools-" + inspectedTabId});
 
   ext.onMessage = port.onMessage;
-  ext.devtools = chrome.devtools;
+  ext.devtools = browser.devtools;
 }());