Move treestatus.js to a model class.

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

Index: Tools/GardeningServer/ui/ct-tree-status-tests.html
diff --git a/Tools/GardeningServer/ui/ct-tree-status-tests.html b/Tools/GardeningServer/ui/ct-tree-status-tests.html
index f14e34a99b590f9d0f06d93606a065d5c23e0a68..56f99a7f6043ca8e0c0895100fb0c87d3ce9c8c2 100644
--- a/Tools/GardeningServer/ui/ct-tree-status-tests.html
+++ b/Tools/GardeningServer/ui/ct-tree-status-tests.html
@@ -48,8 +48,8 @@ asyncTest("basic", 10, function() {
   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([
@@ -65,7 +65,9 @@ asyncTest("basic", 10, 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() {
@@ -73,7 +75,7 @@ asyncTest("basic", 10, function() {
         ok(throttledtree.shadowRoot.textContent.has("throttled-tree-project"));
         ok(closedtree.shadowRoot.textContent.has("closed-tree-project"));
         start();
-        treestatus.urlByName = urlByName;
+        TreeStatus.prototype.urlByName = urlByName;
       });
     });
   });