sheriff-o-matic: add a help link

Adds a link in the toolbar to http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium

BUG=420469

Review URL: https://codereview.chromium.org/696813002

git-svn-id: svn://svn.chromium.org/blink/trunk@184811 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Tools/GardeningServer/ui/ct-unexpected-failures.html

@@ -36,6 +36,7 @@ found in the LICENSE file.
     </style>
     <div class="toolbar">
       <a href="https://code.google.com/p/chromium/wiki/UsefulURLs">Useful URLs</a>
+      <a href="http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium">How to Sheriff</a>
     </div>
     <ct-tree-status status="{{ treeStatuses['chromium'] }}" state="{{ treeStatuses['chromium'].status }}"></ct-tree-status>
     <template if="{{ tree == 'blink' }}">