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

tracing/tracing/ui/base/drag_handle_test.html

Index: tracing/tracing/ui/base/drag_handle_test.html
diff --git a/tracing/tracing/ui/base/drag_handle_test.html b/tracing/tracing/ui/base/drag_handle_test.html
index bd52880503db2c60bb46be76bfa1690bc8f759e7..e0c53b1cb114ddca8259a502317d1e8154ab3fb9 100644
--- a/tracing/tracing/ui/base/drag_handle_test.html
+++ b/tracing/tracing/ui/base/drag_handle_test.html
@@ -27,9 +27,9 @@ tr.b.unittest.testSuite(function() {
     var dragHandle = document.createElement('tr-ui-b-drag-handle');
     dragHandle.target = lowerEl;
 
-    el.appendChild(upperEl);
-    el.appendChild(dragHandle);
-    el.appendChild(lowerEl);
+    Polymer.dom(el).appendChild(upperEl);
+    Polymer.dom(el).appendChild(dragHandle);
+    Polymer.dom(el).appendChild(lowerEl);
     el.upperEl = upperEl;
     el.dragHandle = dragHandle;
     el.lowerEl = lowerEl;
@@ -60,7 +60,7 @@ tr.b.unittest.testSuite(function() {
     var styleEl = document.createElement('style');
     styleEl.textContent =
         '.mode-a { height: 100px; } .mode-b { height: 50px; }';
-    document.head.appendChild(styleEl);
+    Polymer.dom(document.head).appendChild(styleEl);
 
     this.addHTMLOutput(el);