Import polymer in a single place and remove d3 hacks

tracing/tracing/tests.html

Index: tracing/tracing/tests.html
diff --git a/tracing/tracing/tests.html b/tracing/tracing/tests.html
index 7ff1b182b3aecba4574ed35b5ab7d337d6146236..7924c0d039d9b0bef185103c86d83400176f0a8e 100644
--- a/tracing/tracing/tests.html
+++ b/tracing/tracing/tests.html
@@ -12,15 +12,7 @@ found in the LICENSE file.
   <link rel="shortcut icon" href="data:image/x-icon;base64,"
         type="image/x-icon">
 
-  <script src="/components/webcomponentsjs/webcomponents-lite.js"></script>
-  <script>
-    'use strict';
-
-    // Force Polymer into native shadowDom mode
-    window.Polymer = window.Polymer || {};
-    window.Polymer.dom = 'shadow';
-  </script>
-  <link rel="import" href="/components/polymer/polymer.html">
+  <link rel="import" href="/tracing/ui/base/base.html" data-suppress-import-order>
   <link rel="import" href="/tracing/base/unittest/interactive_test_runner.html">
   <style>
     html, body {