Issue 5028 - Use browser namespace

inject.preload.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";
 
 let randomEventName = "abp-request-" + Math.random().toString(36).substr(2);
 
 // Proxy "should we block?" messages from checkRequest inside the injected
 // code to the background page and back again.
 document.addEventListener(randomEventName, event =>
 {
   let {url, requestType} = event.detail;
 
-  chrome.runtime.sendMessage({
+  browser.runtime.sendMessage({
     type: "request.blockedByWrapper",
     requestType,
     url
   }, block =>
   {
     document.dispatchEvent(new CustomEvent(
       randomEventName + "-" + requestType + "-" + url, {detail: block}
     ));
   });
 });
@@ skipping 357 matching lines @@
   if (typeof sandbox != "string" || /(^|\s)allow-scripts(\s|$)/i.test(sandbox))
   {
     let script = document.createElement("script");
     script.type = "application/javascript";
     script.async = false;
     script.textContent = "(" + injected + ")('" + randomEventName + "');";
     document.documentElement.appendChild(script);
     document.documentElement.removeChild(script);
   }
 }