[Sheriff-o-matic] Remove race condition on the commit list.

Tools/GardeningServer/ui/ct-failure-card.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-builder-grid.html">
 <link rel="import" href="ct-commit-list.html">
 <link rel="import" href="ct-test-list.html">
 <link rel="import" href="../bower_components/paper-dialog/paper-dialog.html">
 <link rel="import" href="../bower_components/paper-dialog/paper-dialog-transition.html">
 <link rel="import" href="../bower_components/paper-input/paper-input.html">
 
-<polymer-element name="ct-failure-card" attributes="group commits tree bug">
+<polymer-element name="ct-failure-card" attributes="group commitLog tree bug">
   <template>
     <style>
       :host {
         display: flex;
       }
 
       /* FIXME: All this paper-button styling should go in a cr-button component so that
          we can use buttons in different places and have them all look the same. */
       paper-button {
         -webkit-user-select: none;
@@ skipping 36 matching lines @@
         flex-direction: column;
       }
 
       .snoozed {
         opacity: 0.5;
       }
     </style>
     <ct-builder-grid failures="{{ group.failures }}"></ct-builder-grid>
     <div id="failure" class="{{ { snoozed: group.isSnoozed } | tokenList }}">
       <ct-test-list tests="{{ group.failures }}" tree="{{ tree }}"></ct-test-list>
-      <ct-commit-list commitList="{{ _commits() }}"></ct-commit-list>
+      <ct-commit-list commitList="{{ _commitList }}"></ct-commit-list>
     </div>
     <div id="buttons">
       <paper-button id="examine" on-tap="{{ examine }}" label="Examine"></paper-button>
       <template if="{{ !group.isSnoozed }}">
         <paper-button id="snooze" on-tap="{{ snooze }}" label="Snooze"></paper-button>
       </template>
       <template if="{{ group.isSnoozed }}">
         <paper-button id="snooze" on-tap="{{ unsnooze }}" label="Unsnooze"></paper-button>
       </template>
       <paper-button id="link-bug" on-tap="{{ linkBug }}" label="Link Bug"></paper-button>
       <template if="{{ group.bug !== undefined }}">
         <div>
           <a href="{{ group.bug }}">
             {{ group.bugLabel }}</a>
         </div>
       </template>
     </div>
 
     <paper-dialog heading="Enter bug number" transition="paper-transition-center" id="bugDialog">
       <paper-input label="Bug# or URL" floatingLabel autofocus id="bug"></paper-input>
       <paper-button label="Remove bug link" on-tap="{{ removeBug }}" dismissive id="dialogRemoveBug"></paper-button>
       <paper-button label="OK" on-tap="{{ saveBug }}" affirmative id="dialogOk"></paper-button>
     </paper-dialog>
   </template>
   <script>
     Polymer({
       group: null,
-      commits: null,
+      commitLog: null,
       tree: '',
+      _commitList: null,
+
+      observe: {
+        group: '_updateCommitList',
+        commitLog: '_updateCommitList'
+      },
 
       examine: function() {
         this.fire('ct-examine-failures', this.group);
       },
 
       snooze: function() {
         this.group.snoozeUntil(Date.now() + 60 * 60 * 1000);
       },
 
       unsnooze: function() {
         this.group.unsnooze();
       },
 
-      _commits: function() {
-        if (!this.group)
-          return undefined;
-        return this.group.commitList(this.commits);
+      _updateCommitList: function() {
+        this._commitList = this.group ?
+            this.group.commitList(this.commitLog) : undefined;
       },
 
       linkBug: function() {
         this.$.bug.value = this.group.bug;
         this.$.bugDialog.toggle();
       },
 
       saveBug: function() {
         this.group.setBug(this.$.bug.value);
       },
 
       removeBug: function() {
         this.group.clearBug();
       },
     });
   </script>
 </polymer-element>