Migrate child element manipulation, innerHTML, classList, attributes,

tracing/tracing/ui/base/info_bar.html

Index: tracing/tracing/ui/base/info_bar.html
diff --git a/tracing/tracing/ui/base/info_bar.html b/tracing/tracing/ui/base/info_bar.html
index 1e7bc4e8e35987f089ef9aceaecaed045d781fb5..8e5082538f2f5bab9a33f10c2bbf9ee78593bd9b 100644
--- a/tracing/tracing/ui/base/info_bar.html
+++ b/tracing/tracing/ui/base/info_bar.html
@@ -58,14 +58,14 @@ Polymer({
   },
 
   get visible() {
-    return !this.classList.contains('info-bar-hidden');
+    return !Polymer.dom(this).classList.contains('info-bar-hidden');
   },
 
   set visible(visible) {
     if (visible)
-      this.classList.remove('info-bar-hidden');
+      Polymer.dom(this).classList.remove('info-bar-hidden');
     else
-      this.classList.add('info-bar-hidden');
+      Polymer.dom(this).classList.add('info-bar-hidden');
   },
 
   removeAllButtons: function() {