[MD History] Add full time hover text to dates in history items.

chrome/browser/resources/md_history/history_item.js

Index: chrome/browser/resources/md_history/history_item.js
diff --git a/chrome/browser/resources/md_history/history_item.js b/chrome/browser/resources/md_history/history_item.js
index e064ec6710efbb08bdb2ce0cd7a0d3f1e39c6ef5..e2d0b2549dd92ef2d2943d3f74b19ee7f06c240c 100644
--- a/chrome/browser/resources/md_history/history_item.js
+++ b/chrome/browser/resources/md_history/history_item.js
@@ -300,6 +300,15 @@ cr.define('md_history', function() {
         return this.item.dateRelativeDay;
       return HistoryItem.searchResultsTitle(numberOfItems, search);
     },
+
+    /**
+     * @private
+     */

[Dan Beam, 2016/10/28 20:43:28]

nit: /** @private */

+    addTimeTitle_: function() {
+      var el = this.$['time-accessed'];
+      el.setAttribute('title', new Date(this.item.time).toString());
+      this.unlisten(el, 'mouseover', 'addTimeTitle_');
+    },
   });
 
   /**