Move treestatus.js to a model class.

Tools/GardeningServer/ui/ct-tree-status-tests.html

 <!--
 Copyright 2014 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <link rel="import" href="ct-tree-status.html">
 
 <script>
 (function () {
@@ skipping 30 matching lines @@
   };
 
   var opentree = document.createElement("ct-tree-status");
   opentree.project = "open-tree-project";
   var throttledtree = document.createElement("ct-tree-status");
   throttledtree.project = "throttled-tree-project";
   var closedtree = document.createElement("ct-tree-status");
   closedtree.project = "closed-tree-project";
 
   simulator.runTest(function() {
-    var urlByName = treestatus.urlByName;
-    treestatus.urlByName = function(name) {
+    var urlByName = TreeStatus.prototype.urlByName;
+    TreeStatus.prototype.urlByName = function(name) {
       return "http://" + name + "-status.appspot.com/";
     }
     Promise.all([
       opentree.update().then(function() {
         equal(opentree.status, "open");
       }),
       throttledtree.update().then(function() {
         equal(throttledtree.message,
               "Tree is throttled just for fun by username@test.org");
         equal(throttledtree.status, "throttled");
       }),
       closedtree.update().then(function() {
         equal(closedtree.message,
               "Tree is closed for maintenance by username@test.org");
         equal(closedtree.status, "closed");
-        equal(closedtree.shadowRoot.querySelector('a').href, treestatus.urlByName('closed-tree-project'));
+
+        var treeStatus = new TreeStatus();
+        equal(closedtree.shadowRoot.querySelector('a').href, treeStatus.urlByName('closed-tree-project'));
       })
     ]).then(function() {
       requestAnimationFrame(function() {
         ok(!opentree.shadowRoot.textContent.has("open-tree-project"));
         ok(throttledtree.shadowRoot.textContent.has("throttled-tree-project"));
         ok(closedtree.shadowRoot.textContent.has("closed-tree-project"));
         start();
-        treestatus.urlByName = urlByName;
+        TreeStatus.prototype.urlByName = urlByName;
       });
     });
   });
 });
 
 })();
 </script>