--- a/mobile/android/chrome/content/aboutDownloads.js
+++ b/mobile/android/chrome/content/aboutDownloads.js
@@ -261,18 +261,22 @@ DownloadItem.prototype = {
   },
 
   get stateChanged() {
     return kDownloadStatePropertyNames.some(
       name => this._state[name] != this._download[name],
       this);
   },
 
-  get download() this._download,
-  get element() this._element,
+  get download() {
+    return this._download;
+  },
+  get element() {
+    return this._element;
+  },
 
   createElement: function() {
     let template = document.getElementById("download-item");
     // TODO: use this once <template> is working
     // let element = document.importNode(template.content, true);
 
     // simulate a <template> node...
     let element = template.cloneNode(true);
@@ -307,20 +311,28 @@ DownloadItem.prototype = {
   },
 
   onDownloadChanged: function () {
     this._updateFromDownload();
     this.updateElement(this.element);
   },
 
   // template properties below
-  get domain() this._domain,
-  get fileName() this._fileName,
-  get id() this._id,
-  get iconUrl() this._iconUrl,
+  get domain() {
+    return this._domain;
+  },
+  get fileName() {
+    return this._fileName;
+  },
+  get id() {
+    return this._id;
+  },
+  get iconUrl() {
+    return this._iconUrl;
+  },
 
   get size() {
     if (this.download.hasProgress) {
       return DownloadUtils.convertByteUnits(this.download.totalBytes).join("");
     }
     return strings.GetStringFromName("downloadState.unknownSize");
   },
 

--- a/mobile/android/chrome/content/aboutLogins.js
+++ b/mobile/android/chrome/content/aboutLogins.js
@@ -4,17 +4,17 @@
 
 var Ci = Components.interfaces, Cc = Components.classes, Cu = Components.utils;
 
 Cu.import("resource://gre/modules/Messaging.jsm");
 Cu.import("resource://gre/modules/Services.jsm")
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/TelemetryStopwatch.jsm");
 
-XPCOMUtils.defineLazyGetter(window, "gChromeWin", function()
+XPCOMUtils.defineLazyGetter(window, "gChromeWin", () =>
   window.QueryInterface(Ci.nsIInterfaceRequestor)
     .getInterface(Ci.nsIWebNavigation)
     .QueryInterface(Ci.nsIDocShellTreeItem)
     .rootTreeItem
     .QueryInterface(Ci.nsIInterfaceRequestor)
     .getInterface(Ci.nsIDOMWindow)
     .QueryInterface(Ci.nsIDOMChromeWindow));
 

--- a/mobile/android/chrome/content/aboutPrivateBrowsing.js
+++ b/mobile/android/chrome/content/aboutPrivateBrowsing.js
@@ -6,17 +6,17 @@
 
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/PrivateBrowsingUtils.jsm");
 
-XPCOMUtils.defineLazyGetter(window, "gChromeWin", function()
+XPCOMUtils.defineLazyGetter(window, "gChromeWin", () =>
   window.QueryInterface(Ci.nsIInterfaceRequestor)
     .getInterface(Ci.nsIWebNavigation)
     .QueryInterface(Ci.nsIDocShellTreeItem)
     .rootTreeItem
     .QueryInterface(Ci.nsIInterfaceRequestor)
     .getInterface(Ci.nsIDOMWindow)
     .QueryInterface(Ci.nsIDOMChromeWindow));
 

--- a/mobile/android/tests/browser/robocop/robocop_head.js
+++ b/mobile/android/tests/browser/robocop/robocop_head.js
@@ -429,19 +429,19 @@ function todo_check_null(condition, stac
  * do_check_matches({a:1, b:{c:2,d:undefined}}, {a:1, b:{c:2,d:3}})
  *
  * // 'length' property counts, even if non-enumerable.
  * do_check_matches([3,4,5], [3,4,5])     // pass
  * do_check_matches([3,4,5], [3,5,5])     // fail; value doesn't match
  * do_check_matches([3,4,5], [3,4,5,6])   // fail; length doesn't match
  *
  * // functions in patterns get applied.
- * do_check_matches({foo:function (v) v.length == 2}, {foo:"hi"}) // pass
- * do_check_matches({foo:function (v) v.length == 2}, {bar:"hi"}) // fail
- * do_check_matches({foo:function (v) v.length == 2}, {foo:"hello"}) // fail
+ * do_check_matches({foo:v => v.length == 2}, {foo:"hi"}) // pass
+ * do_check_matches({foo:v => v.length == 2}, {bar:"hi"}) // fail
+ * do_check_matches({foo:v => v.length == 2}, {foo:"hello"}) // fail
  *
  * // We don't check constructors, prototypes, or classes. However, if
  * // pattern has a 'length' property, we require values to match that as
  * // well, even if 'length' is non-enumerable in the pattern. So arrays
  * // are useful as patterns.
  * do_check_matches({0:0, 1:1, length:2}, [0,1])  // pass
  * do_check_matches({0:1}, [1,2])                 // pass
  * do_check_matches([0], {0:0, length:1})         // pass