ES6ify /gr-change-star/*

Bug: Issue 6179
Change-Id: Ieea375e9d9e7ccd8fdfa4545f540da1e5fc1ddbd
diff --git a/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js b/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js
index beb0ff1..0e5ff04 100644
--- a/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js
+++ b/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star.js
@@ -26,16 +26,16 @@
       _xhrPromise: Object,  // Used for testing.
     },
 
-    _computeStarClass: function(starred) {
-      var classes = ['starButton'];
+    _computeStarClass(starred) {
+      const classes = ['starButton'];
       if (starred) {
         classes.push('starButton-active');
       }
       return classes.join(' ');
     },
 
-    toggleStar: function() {
-      var newVal = !this.change.starred;
+    toggleStar() {
+      const newVal = !this.change.starred;
       this.set('change.starred', newVal);
       this._xhrPromise = this.$.restAPI.saveChangeStarred(this.change._number,
           newVal);
diff --git a/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star_test.html b/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star_test.html
index 460d860..6286efe 100644
--- a/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-change-star/gr-change-star_test.html
@@ -33,12 +33,12 @@
 </test-fixture>
 
 <script>
-  suite('gr-change-star tests', function() {
-    var element;
+  suite('gr-change-star tests', () => {
+    let element;
 
-    setup(function() {
+    setup(() => {
       stub('gr-rest-api-interface', {
-        saveChangeStarred: function() { return Promise.resolve({ok: true}); },
+        saveChangeStarred() { return Promise.resolve({ok: true}); },
       });
       element = fixture('basic');
       element.change = {
@@ -47,7 +47,7 @@
       };
     });
 
-    test('star visibility states', function() {
+    test('star visibility states', () => {
       element.set('change.starred', true);
       assert.isTrue(element.$$('button').classList.contains('starButton'));
       assert.isTrue(
@@ -59,21 +59,21 @@
           element.$$('button').classList.contains('starButton-active'));
     });
 
-    test('starring', function(done) {
+    test('starring', done => {
       element.set('change.starred', false);
       MockInteractions.tap(element.$$('button'));
 
-      element._xhrPromise.then(function(req) {
+      element._xhrPromise.then(req => {
         assert.equal(element.change.starred, true);
         done();
       });
     });
 
-    test('unstarring', function(done) {
+    test('unstarring', done => {
       element.set('change.starred', true);
       MockInteractions.tap(element.$$('button'));
 
-      element._xhrPromise.then(function(req) {
+      element._xhrPromise.then(req => {
         assert.equal(element.change.starred, false);
         done();
       });