Migrate child element manipulation, innerHTML, classList, attributes,

tracing/tracing/value/ui/scalar_span.html

Index: tracing/tracing/value/ui/scalar_span.html
diff --git a/tracing/tracing/value/ui/scalar_span.html b/tracing/tracing/value/ui/scalar_span.html
index 4a6c1e20740449745f9a0606735d5d60bc7250bd..7775781398b1493c668fc20147ae16252c6efc56 100644
--- a/tracing/tracing/value/ui/scalar_span.html
+++ b/tracing/tracing/value/ui/scalar_span.html
@@ -150,14 +150,14 @@ Polymer({
   },
 
   get rightAlign() {
-    return this.$.content.classList.contains('right-align');
+    return Polymer.dom(this.$.content).classList.contains('right-align');
   },
 
   set rightAlign(rightAlign) {
     if (rightAlign)
-      this.$.content.classList.add('right-align');
+      Polymer.dom(this.$.content).classList.add('right-align');
     else
-      this.$.content.classList.remove('right-align');
+      Polymer.dom(this.$.content).classList.remove('right-align');
   },
 
   updateSparkline_: function() {