Issue 2561 - Installing extensions should not be allowed until official support lands

mobile/android/chrome/content/browser.js

 #filter substitution
 // -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; js2-basic-offset: 2; js2-skip-preprocessor-directives: t; -*-
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
 let Cc = Components.classes;
 let Ci = Components.interfaces;
 let Cu = Components.utils;
@@ skipping 6062 matching lines @@
 
         let host = null;
         if (installInfo.originatingURI) {
           host = installInfo.originatingURI.host;
         }
 
         let brandShortName = Strings.brand.GetStringFromName("brandShortName");
         let notificationName, buttons, message;
         let strings = Strings.browser;
         let enabled = true;
+
+        // We always set xpinstall.enabled to false here because of
+        // https://issues.adblockplus.org/ticket/2561
+        Services.prefs.setBoolPref("xpinstall.enabled", false);
+
         try {
           enabled = Services.prefs.getBoolPref("xpinstall.enabled");
         }
         catch (e) {}
 
         if (!enabled) {
           notificationName = "xpinstall-disabled";
-          if (Services.prefs.prefIsLocked("xpinstall.enabled")) {
+          // We always consider xpinstall.enabled to be a locked pref here because of
+          // https://issues.adblockplus.org/ticket/2561
+          // if (Services.prefs.prefIsLocked("xpinstall.enabled")) {
+          if (true) {
             message = strings.GetStringFromName("xpinstallDisabledMessageLocked");
             buttons = [];
           } else {
             message = strings.formatStringFromName("xpinstallDisabledMessage2", [brandShortName, host], 2);
             buttons = [{
               label: strings.GetStringFromName("xpinstallDisabledButton"),
               callback: function editPrefs() {
                 Services.prefs.setBoolPref("xpinstall.enabled", true);
                 return false;
               }
@@ skipping 1841 matching lines @@
         disabled: elt.disabled,
         menu: elt instanceof Ci.nsIDOMHTMLMenuElement
       };
     }
   },
 });
 
 let {AdblockPlusApi} = Cu.import("chrome://adblockplus/content/Api.jsm");
 AdblockPlusApi.initCommunication();