Expand patchset if patchsetID provided in URL

appengine/chromium_rietveld/new_static/components/cr-issue-patchsets.html

 <!-- Copyright (c) 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. -->
 
 <link rel="import" href="../common/cr-collapsible.html">
 <link rel="import" href="cr-issue-patchset.html">
 <link rel="import" href="cr-patchset-header.html">
 
 <polymer-element name="cr-issue-patchsets" attributes="patchsets">
     <template>
@@ skipping 58 matching lines @@
         <cr-keyboard on-key-e="{{ handleExpandKey }}" global></cr-keyboard>
     </template>
     <script>
         Polymer({
             created: function() {
                 this.patchsets = null;
                 this.showOlderPatchsets = false;
                 this.olderPatchsets = null;
                 this.currentPatchset = null;
             },
+            attached: function() {
+                if (window.location.hash.startsWith('#ps')) {
+                  var psId = parseInt(window.location.hash.substring(3));
+                  this.showOlderPatchsets = true;
+                  this.patchsets.forEach(function(patchset) {
+                    patchset.active = (patchset.id == psId);
+                  });
+                }
+            },
             patchsetsChanged: function(oldValue, newValue) {
                 var value = newValue || [];
                 this.olderPatchsets = value.to(-1);
                 this.currentPatchset = value.last();
-                this.showOlderPatchsets = false;
             },
             pluralize: function(text, count) {
                 if (!count)
                     return "";
                 if (count == 1)
                     return text;
                 return text.pluralize();
             },
             handleShowOlderPatchsets: function() {
                 this.showOlderPatchsets = true;
             },
             handleExpandKey: function(event) {
                 event.preventDefault();
                 var sections = this.shadowRoot.querySelectorAll(".patchset");
                 var last = sections[sections.length - 1];
                 if (!last)
                     return;
                 last.active = true;
                 last.querySelector("cr-issue-patchset").expandAllDiffs().then(function() {
                     last.scrollIntoView(true);
                 });
             },
         });
     </script>
 </polymer-element>