Use Polymer.dom with insertBefore.

tracing/tracing/ui/base/table.html

Index: tracing/tracing/ui/base/table.html
diff --git a/tracing/tracing/ui/base/table.html b/tracing/tracing/ui/base/table.html
index d0e2405b69181d284a7c82f50935814b92f9912e..2b2cb51b4a8440861c91d1fbb8ca6038cc193cff 100644
--- a/tracing/tracing/ui/base/table.html
+++ b/tracing/tracing/ui/base/table.html
@@ -574,11 +574,13 @@ tr.exportTo('tr.ui.b', function() {
 
           if (lastAddedRow === undefined) {
             // Put first into the table.
-            tableSection.insertBefore(htmlNode, tableSection.firstChild);
+            Polymer.dom(tableSection).insertBefore(
+                htmlNode, tableSection.firstChild);
           } else {
             // This is shorthand for insertAfter(htmlNode, lastAdded).
             var nextSiblingOfLastAdded = lastAddedRow.nextSibling;
-            tableSection.insertBefore(htmlNode, nextSiblingOfLastAdded);
+            Polymer.dom(tableSection).insertBefore(
+                htmlNode, nextSiblingOfLastAdded);
           }
           this.updateTabIndexForTableRowNode_(htmlNode);