Change the expand button to unfold-more.

Tools/GardeningServer/ui/ct-test-list.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="../bower_components/paper-icon-button/paper-icon-button.html">
 
 <polymer-element name="ct-test-list" attributes="tests tree">
   <template>
@@ skipping 29 matching lines @@
             <div>
               {{ groups.step }}
               <a href="{{ test | flakinessDashboardURL }}">{{ test.testName }}</a>
             </div>
           </template>
         </template>
         <!-- Case 3: group of tests failed -->
         <template if="{{ group.name && group.tests.length > 1 && !group.expanded }}">
           <div>
             {{ groups.step }} {{ group.name }} ({{ group.tests.length }} Tests)
-            <paper-icon-button id="expand" icon="more-vert" step="{{ groups.step }}" group="{{ group.name }}" on-click="{{ _expand }}"></paper-icon-button>
+            <paper-icon-button id="expand" icon="unfold-more" step="{{ groups.step }}" group="{{ group.name }}" on-click="{{ _expand }}"></paper-icon-button>
           </div>
         </template>
       </template>
     </template>
   </template>
   <script>
     Polymer('ct-test-list', {
       testsChanged: function() {
         var groups = {};
         if (this.tests) {
@@ skipping 33 matching lines @@
           }
         });
       },
 
       flakinessDashboardURL: function(test) {
         return test.flakinessDashboardURL(this.tree);
       },
     });
   </script>
 </polymer-element>