[MD History] Fix toolbar dates in grouped mode.

chrome/browser/resources/md_history/history_toolbar.js

Index: chrome/browser/resources/md_history/history_toolbar.js
diff --git a/chrome/browser/resources/md_history/history_toolbar.js b/chrome/browser/resources/md_history/history_toolbar.js
index fbe0359cf4e4a7509cf13028eea962723dd3b986..d0fa68ef4d251fbcd07b4d772bee9be6334cf4a2 100644
--- a/chrome/browser/resources/md_history/history_toolbar.js
+++ b/chrome/browser/resources/md_history/history_toolbar.js
@@ -51,15 +51,11 @@ Polymer({
       notify: true,
     },
 
-    querying: Boolean,
-
     hasMoreResults: Boolean,
 
-    // The start time of the query range.
-    queryStartTime: String,
+    querying: Boolean,
 
-    // The end time of the query range.
-    queryEndTime: String,
+    queryInfo: Object,
 
     // Whether to show the menu promo (a tooltip that points at the menu button
     // in narrow mode).
@@ -131,10 +127,15 @@ Polymer({
   },
 
   /** @private */
-  getHistoryInterval_: function(queryStartTime, queryEndTime) {
-    // TODO(calamity): Fix the format of these dates.
-    return loadTimeData.getStringF(
-      'historyInterval', queryStartTime, queryEndTime);
+  getHistoryInterval_: function() {
+    var info = this.queryInfo;
+    if (this.groupedRange == HistoryRange.WEEK) {
+      return loadTimeData.getStringF(
+        'historyInterval', info.queryStartTimeShort, info.queryEndTimeShort);
+    }
+
+    if (this.groupedRange == HistoryRange.MONTH)
+      return info.queryStartMonth;
   },
 
   /** @private */