Use Polymer.dom with many dom manipulations.

tracing/tracing/base/base.html

Index: tracing/tracing/base/base.html
diff --git a/tracing/tracing/base/base.html b/tracing/tracing/base/base.html
index 53239739c8c6c0b0ade3d9f9dfc8608b9ef63f66..516276f11a34b12b8030584362d9010be93b1b0a 100644
--- a/tracing/tracing/base/base.html
+++ b/tracing/tracing/base/base.html
@@ -119,11 +119,13 @@ this.tr = (function() {
 
     showPanicElementIfNeeded();
     var panicMessageEl = document.createElement('div');
-    panicMessageEl.innerHTML =
+    Polymer.dom(panicMessageEl).innerHTML =
         '<h2 id="message"></h2>' +
         '<pre id="details"></pre>';
-    panicMessageEl.querySelector('#message').textContent = panicTitle;
-    panicMessageEl.querySelector('#details').textContent = panicDetails;
+    Polymer.dom(panicMessageEl).querySelector('#message').
+        textContent = panicTitle;
+    Polymer.dom(panicMessageEl).querySelector('#details').
+        textContent = panicDetails;
     Polymer.dom(panicElement).appendChild(panicMessageEl);
 
     rawPanicMessages.push({