Add analytics to sheriff-o-matic.

Tools/GardeningServer/lib/analytics.html

+<!--
+Copyright 2014 The Chromium Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+-->
+
+<!--
+This is a copy of the Google Analytics snippet obtained from
+http://www.google.com/analytics/.
+-->
+
+<script>
+  function Analytics(trackingId){
+    (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
+    (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
+    m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
+    })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
+
+    ga('create', trackingId, 'auto');
+    ga('send', 'pageview');
+  }
+</script>