Use the non-deprecated way to set the button labels

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">
 
@@ skipping 52 matching lines @@
       }
     </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 first="{{ group.failures[0].lastPassingRevisions }}"
           last="{{ group.failures[0].firstFailingRevisions }}"
           commits="{{ commits }}"></ct-commit-list>
     </div>
     <div id="buttons">
-      <paper-button id="examine" on-tap="{{ examine }}">Examine</paper-button>
+      <paper-button id="examine" on-tap="{{ examine }}" label="Examine"></paper-button>
       <template if="{{ !group.isSnoozed }}">
-        <paper-button id="snooze" on-tap="{{ snooze }}">Snooze</paper-button>
+        <paper-button id="snooze" on-tap="{{ snooze }}" label="Snooze"></paper-button>
       </template>
       <template if="{{ group.isSnoozed }}">
-        <paper-button id="snooze" on-tap="{{ unsnooze }}">Unsnooze</paper-button>
+        <paper-button id="snooze" on-tap="{{ unsnooze }}" label="Unsnooze"></paper-button>
       </template>
     </div>
   </template>
   <script>
     Polymer({
       group: null,
       commits: {},
       tree: '',
 
       examine: function() {
         this.fire('ct-examine-failures', this.group);
       },
 
       snooze: function() {
         this.group.snoozeUntil(Date.now() + 60 * 60 * 1000);
       },
 
       unsnooze: function() {
         this.group.unsnooze();
       },
     });
   </script>
 </polymer-element>