[polymer] Switches .appendChild() to Polymer.dom()...appendChild()

tracing/tracing/ui/extras/about_tracing/record_controller.html

Index: tracing/tracing/ui/extras/about_tracing/record_controller.html
diff --git a/tracing/tracing/ui/extras/about_tracing/record_controller.html b/tracing/tracing/ui/extras/about_tracing/record_controller.html
index 2284b0fa3e7dd250a9b57d36bd72cba9e9d32129..e757c21c698f0ea60f62803dcabef15a54d3775d 100644
--- a/tracing/tracing/ui/extras/about_tracing/record_controller.html
+++ b/tracing/tracing/ui/extras/about_tracing/record_controller.html
@@ -76,14 +76,14 @@ tr.exportTo('tr.ui.e.about_tracing', function() {
       progressDlg.userCanClose = false;
 
       bufferPercentFullDiv = document.createElement('div');
-      progressDlg.appendChild(bufferPercentFullDiv);
+      Polymer.dom(progressDlg).appendChild(bufferPercentFullDiv);
 
       var stopButton = document.createElement('button');
       stopButton.textContent = 'Stop';
       progressDlg.clickStopButton = function() {
         stopButton.click();
       };
-      progressDlg.appendChild(stopButton);
+      Polymer.dom(progressDlg).appendChild(stopButton);
 
       var recordingOptions = {
         categoryFilter: selectionDlg.categoryFilter(),