Bug 1346722 - Display permissions in alphabetical order. r=aswan

-Create a copy of the permissions array and sort it.
-Change permissions order in test

browser/base/content/test/webextensions/head.js

@@ -315,8 +315,10 @@ async function testInstallMethod(installFn, telemetryBase) {
         ["webextPerms.hostDescription.wildcard", "wildcard.domain"],
         ["webextPerms.hostDescription.oneSite", "singlehost.domain"],
         ["webextPerms.description.nativeMessaging"],
-        ["webextPerms.description.tabs"],
+        // The below permissions are deliberately in this order as permissions
+        // are sorted alphabetically by the permission string to match AMO.
         ["webextPerms.description.history"],
+        ["webextPerms.description.tabs"],
       ]);
     } else if (filename == NO_PERMS_XPI) {
       checkNotification(panel, isDefaultIcon, []);

toolkit/components/extensions/Extension.jsm

@@ -904,8 +904,11 @@ this.ExtensionData = class {
       result.msgs.push(bundle.formatStringFromName(permissionKey(NATIVE_MSG_PERM), [info.appName], 1));
     }
 
-    // Finally, show remaining permissions, in any order.
-    for (let permission of perms.permissions) {
+    // Finally, show remaining permissions, in the same order as AMO.
+    // The permissions are sorted alphabetically by the permission
+    // string to match AMO.
+    let permissionsCopy = perms.permissions.slice(0);
+    for (let permission of permissionsCopy.sort()) {
       // Handled above
       if (permission == "nativeMessaging") {
         continue;