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

tracing/tracing/ui/base/overlay.html

Index: tracing/tracing/ui/base/overlay.html
diff --git a/tracing/tracing/ui/base/overlay.html b/tracing/tracing/ui/base/overlay.html
index df8e13ceddf7ee9e3377cb70678bf489c83518b1..0ff1c753d1b217cdfae054c056375005b7442d01 100644
--- a/tracing/tracing/ui/base/overlay.html
+++ b/tracing/tracing/ui/base/overlay.html
@@ -162,8 +162,8 @@ tr.exportTo('tr.ui.b', function() {
       var createShadowRoot = this.createShadowRoot ||
           this.webkitCreateShadowRoot;
       this.shadow_ = createShadowRoot.call(this);
-      this.shadow_.appendChild(tr.ui.b.instantiateTemplate('#overlay-template',
-                                                        THIS_DOC));
+      Polymer.dom(this.shadow_).appendChild(
+          tr.ui.b.instantiateTemplate('#overlay-template', THIS_DOC));
 
       this.closeBtn_ = this.shadow_.querySelector('close-button');
       this.closeBtn_.addEventListener('click', this.onClose_);
@@ -218,7 +218,7 @@ tr.exportTo('tr.ui.b', function() {
     },
 
     show_: function() {
-      this.parentEl_.appendChild(this);
+      Polymer.dom(this.parentEl_).appendChild(this);
 
       if (this.userCanClose_) {
         this.addEventListener('keydown', this.onKeyDown_.bind(this));
@@ -328,7 +328,7 @@ tr.exportTo('tr.ui.b', function() {
     b.addEventListener('click', function() {
       o.visible = false;
     });
-    o.buttons.appendChild(b);
+    Polymer.dom(o.buttons).appendChild(b);
     o.visible = true;
     return o;
   }