Add a "Link Bug" button to associate a bug with a failure

Tools/GardeningServer/model/test/ct-failure-group-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-failure-group.html">
 
 <script>
 (function () {
@@ skipping 21 matching lines @@
       var group = new CTFailureGroup('key', []);
       group.snoozeUntil(Date.now() + 1000 * 1000).then(function() {
         group.unsnooze().then(function() {
           assert.isFalse(group.isSnoozed);
           done();
         });
       });
     });
   });
 
+  describe('setBug', function() {
+    it('should store the bug and set hasBug', function(done) {
+      var group = new CTFailureGroup('key', []);
+      group.setBug(123).then(function() {
+        assert.isTrue(group.hasBug);
+        assert.equal(group.annotation.bugNumber, 123);
+        done();
+      });
+    });
+  });
+
   describe('annotations', function() {
     it('should have sensible defaults', function() {
       var group = new CTFailureGroup('key', []);
       assert.deepEqual(group.annotation, {});
       assert.isFalse(group.isSnoozed);
     });
 
     it('should compute properties', function() {
-      var group = new CTFailureGroup('key', [], {snoozeTime: Date.now() + 1000 * 1000});
+      var group = new CTFailureGroup('key', [], {snoozeTime: Date.now() + 1000 * 1000, bugNumber: 123});
       assert.isTrue(group.isSnoozed);
+      assert.isTrue(group.hasBug);
     });
 
     it('should be persisted', function(done) {
       var group = new CTFailureGroup('key', []);
       group.snoozeUntil(123).then(function() {
-        CTFailureGroup.fetchAnnotations().then(function(annotations) {
-          assert.deepEqual(annotations['key'], {snoozeTime: 123});
-          done();
+        group.setBug(456).then(function() {
+          CTFailureGroup.fetchAnnotations().then(function(annotations) {
+            assert.deepEqual(annotations['key'], {snoozeTime: 123, bugNumber: 456});
+            done();
+          });
         });
       });
     });
   });
 });
 
 })()
 </script>