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

mobile/android/chrome/content/browser.js

Index: mobile/android/chrome/content/browser.js
diff --git a/mobile/android/chrome/content/browser.js b/mobile/android/chrome/content/browser.js
index 1f1fb6f45064cf9327af29444a31a69f0a49787c..809e2f00d5c3b1c8d0b0b67c5d3f2604d681a33b 100644
--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -6080,6 +6080,11 @@ var XPInstallObserver = {
         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");
         }
@@ -6087,7 +6092,10 @@ var XPInstallObserver = {
 
         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 {