--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -34,25 +34,16 @@ module.exports = {
       "browser/base/content/urlbarBindings.xml",
       "browser/components/search/content/search.xml",
       "browser/components/translation/translation-infobar.xml",
       "toolkit/components/prompts/content/tabprompts.xml"
     ],
     "env": {
       "mozilla/browser-window": true
     }
-  },{
-    // XXX Bug 1421969. These files/directories are still being fixed,
-    // so turn off mozilla/use-services for them for now.
-    "files": [
-      "extensions/pref/**",
-    ],
-    "rules": {
-      "mozilla/use-services": "off",
-    }
   }, {
     // XXX Bug 1436303. These directories are still being fixed, so turn off
     // mozilla/no-cc-etc for now.
     "files": [
       "devtools/**"
     ],
     "rules": {
       "mozilla/no-define-cc-etc": "off",

--- a/extensions/pref/autoconfig/src/prefcalls.js
+++ b/extensions/pref/autoconfig/src/prefcalls.js
@@ -6,16 +6,19 @@
 
 const nsILDAPURL = Ci.nsILDAPURL;
 const LDAPURLContractID = "@mozilla.org/network/ldap-url;1";
 const nsILDAPSyncQuery = Ci.nsILDAPSyncQuery;
 const LDAPSyncQueryContractID = "@mozilla.org/ldapsyncquery;1";
 const nsIPrefService = Ci.nsIPrefService;
 const PrefServiceContractID = "@mozilla.org/preferences-service;1";
 
+// ChromeUtils isn't available here, so we can't use Services.*
+/* eslint-disable mozilla/use-services */
+
 var gVersion;
 var gIsUTF8;
 
 function getPrefBranch() {
 
     var prefService = Cc[PrefServiceContractID]
                         .getService(nsIPrefService);
     return prefService.getBranch(null);

--- a/extensions/pref/autoconfig/test/unit/test_autoconfig_nonascii.js
+++ b/extensions/pref/autoconfig/test/unit/test_autoconfig_nonascii.js
@@ -1,35 +1,30 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /* eslint no-unsafe-finally: "off"*/
 /* Turning off this rule to allow control flow operations in finally block
  * http://eslint.org/docs/rules/no-unsafe-finally  */
+
+ChromeUtils.import("resource://gre/modules/Services.jsm");
+
 function run_test() {
-  let dirSvc = Cc["@mozilla.org/file/directory_service;1"].
-               getService(Ci.nsIProperties);
-  let obsvc = Cc["@mozilla.org/observer-service;1"].
-              getService(Ci.nsIObserverService);
-  let ps = Cc["@mozilla.org/preferences-service;1"].
-           getService(Ci.nsIPrefService);
-  let prefs = ps.getBranch(null);
-
-  let greD = dirSvc.get("GreD", Ci.nsIFile);
-  let defaultPrefD = dirSvc.get("PrfDef", Ci.nsIFile);
+  let greD = Services.dirsvc.get("GreD", Ci.nsIFile);
+  let defaultPrefD = Services.dirsvc.get("PrfDef", Ci.nsIFile);
   let testDir = do_get_cwd();
 
   try {
     let autoConfigJS = testDir.clone();
     autoConfigJS.append("autoconfig.js");
     autoConfigJS.copyTo(defaultPrefD, "autoconfig.js");
 
     // Make sure nsReadConfig is initialized.
     Cc["@mozilla.org/readconfig;1"].getService(Ci.nsISupports);
-    ps.resetPrefs();
+    Services.prefs.resetPrefs();
 
     var tests = [{
       filename: "autoconfig-utf8.cfg",
       prefs: {
         "_test.string.ASCII": "UTF-8",
         "_test.string.non-ASCII": "日本語",
         "_test.string.getPref": "日本語",
         "_test.string.gIsUTF8": "true"
@@ -42,34 +37,34 @@ function run_test() {
         "_test.string.getPref": "日本語",
         "_test.string.gIsUTF8": "false",
       }
     }];
 
     function testAutoConfig(test) {
       // Make sure pref values are unset.
       for (let prefName in test.prefs) {
-        Assert.equal(Ci.nsIPrefBranch.PREF_INVALID, prefs.getPrefType(prefName));
+        Assert.equal(Ci.nsIPrefBranch.PREF_INVALID, Services.prefs.getPrefType(prefName));
       }
 
       let autoConfigCfg = testDir.clone();
       autoConfigCfg.append(test.filename);
       autoConfigCfg.copyTo(greD, "autoconfig.cfg");
 
-      obsvc.notifyObservers(ps, "prefservice:before-read-userprefs");
+      Services.obs.notifyObservers(Services.prefs, "prefservice:before-read-userprefs");
 
       for (let prefName in test.prefs) {
         Assert.equal(test.prefs[prefName],
-                     prefs.getStringPref(prefName));
+                     Services.prefs.getStringPref(prefName));
       }
 
-      ps.resetPrefs();
+      Services.prefs.resetPrefs();
       // Make sure pref values are reset.
       for (let prefName in test.prefs) {
-        Assert.equal(Ci.nsIPrefBranch.PREF_INVALID, prefs.getPrefType(prefName));
+        Assert.equal(Ci.nsIPrefBranch.PREF_INVALID, Services.prefs.getPrefType(prefName));
       }
     }
 
     tests.forEach(testAutoConfig);
 
   } finally {
     try {
       let autoConfigJS = defaultPrefD.clone();
@@ -86,11 +81,11 @@ function run_test() {
       autoConfigCfg.append("autoconfig.cfg");
       autoConfigCfg.remove(false);
     } catch (e) {
       if (e.result != Cr.NS_ERROR_FILE_NOT_FOUND) {
         throw e;
       }
     }
 
-    ps.resetPrefs();
+    Services.prefs.resetPrefs();
   }
 }