[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..abd3d1b22c61cf5d371b6c7f78ce7e262a61d0b9 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);
     },
+
+    /**
+     * @param {HistoryItem} item
+     * @return {string} The full time string for this item.
+     * @private
+     */
+    getTimeTitle_: function(item) {
+      return new Date(item.time).toString();

[Dan Beam, 2016/10/28 03:41:40]

nit: can we lazily generate this?  does doing this have an perf effect?

[calamity, 2016/10/28 06:01:58]

Good catch. Across 60 items, this saves ~5ms. *shrug*

Done.

+    },
   });
 
   /**