Migrate child element manipulation, innerHTML, classList, attributes,

tracing/tracing/ui/base/pie_chart.html

Index: tracing/tracing/ui/base/pie_chart.html
diff --git a/tracing/tracing/ui/base/pie_chart.html b/tracing/tracing/ui/base/pie_chart.html
index 5edfd795219154d80cbdb9588e34564031201095..294911847a6d979b68bcea3dcce4ad36be962305 100644
--- a/tracing/tracing/ui/base/pie_chart.html
+++ b/tracing/tracing/ui/base/pie_chart.html
@@ -5,9 +5,9 @@ Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 <link rel="import" href="/tracing/base/range.html">
+<link rel="import" href="/tracing/ui/base/chart_base.html">
 <link rel="import" href="/tracing/ui/base/d3.html">
 <link rel="import" href="/tracing/ui/base/dom_helpers.html">
-<link rel="import" href="/tracing/ui/base/chart_base.html">
 <link rel="stylesheet" href="/tracing/ui/base/pie_chart.css">
 
 <script>
@@ -29,7 +29,7 @@ tr.exportTo('tr.ui.b', function() {
 
     decorate: function() {
       ChartBase.prototype.decorate.call(this);
-      this.classList.add('pie-chart');
+      Polymer.dom(this).classList.add('pie-chart');
 
       this.data_ = undefined;
       this.seriesKeys_ = undefined;