Highlight file list header on old patch sets

+ Additionally, provide a link to go to the latest patch set
  if an old change is shown.

Change-Id: I25b8bb667473e4701fb1d06514450602eafd999a

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js

diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index 7e67ac0..5484029 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -390,6 +390,14 @@
       return allPatchSets[allPatchSets.length - 1];
     },
 
+    _computePatchInfoClass: function(patchNum, allPatchSets) {
+      if (parseInt(patchNum, 10) ===
+          this._computeLatestPatchNum(allPatchSets)) {
+        return '';
+      }
+      return 'patchInfo--oldPatchSet';
+    },
+
     _computeAllPatchSets: function(change) {
       var patchNums = [];
       for (var rev in change.revisions) {