[MD History] Copy stats from the old history page.

chrome/browser/resources/md_history/constants.js

 // Copyright 2016 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.
 
 // Globals:
 /** @const */ var RESULTS_PER_PAGE = 150;
 
 /**
  * Amount of time between pageviews that we consider a 'break' in browsing,
  * measured in milliseconds.
  * @const
  */
 var BROWSING_GAP_TIME = 15 * 60 * 1000;
 
 /**
  * Maximum length of a history item title. Anything longer than this will be
  * cropped to fit within this limit. This value is large enough that it will not
  * be noticeable in a 960px wide history-item.
  * @const
  */
 var TITLE_MAX_LENGTH = 300;
 
 /**
+ * The largest bucket value for UMA histogram, based on entry ID. All entries
+ * with IDs greater than this will be included in this bucket.
+ * @const
+ */
+var UMA_MAX_BUCKET_VALUE = 1000;
+
+/**
+ * The largest bucket value for a UMA histogram that is a subset of above.
+ * @const
+ */
+var UMA_MAX_SUBSET_BUCKET_VALUE = 100;
+
+/**
  * Histogram buckets for UMA tracking of which view is being shown to the user.
  * @enum {number}
  */
 var HistoryViewHistogram = {
   HISTORY: 0,
   GROUPED_WEEK: 1,
   GROUPED_MONTH: 2,
   SYNCED_TABS: 3,
   SIGNIN_PROMO: 4,
   END: 5,  // Should always be last.
 };
 
 /**
+ * @const
+ */
+var SYNCED_TABS_HISTOGRAM_NAME = 'HistoryPage.OtherDevicesMenu';
+
+/**
+ * Histogram buckets for UMA tracking of synced tabs.
+ * @const
+ */
+var SyncedTabsHistogram = {
+  INITIALIZED: 0,
+  SHOW_MENU_DEPRECATED: 1,
+  LINK_CLICKED: 2,
+  LINK_RIGHT_CLICKED_DEPRECATED: 3,

[tsergeant, 2016/08/18 04:14:34]

Why are these deprecated? This one and 'SHOW_SESSION_MENU' seem like they could
still be collected.

[calamity, 2016/08/19 13:59:43]

I suppose I can add these. They just didn't exist back in the old history page
anymore..

Done.

+  SESSION_NAME_RIGHT_CLICKED_DEPRECATED: 4,
+  SHOW_SESSION_MENU_DEPRECATED: 5,
+  COLLAPSE_SESSION: 6,
+  EXPAND_SESSION: 7,
+  OPEN_ALL: 8,
+  HAS_FOREIGN_DATA: 9,
+  HIDE_FOR_NOW: 10,
+  LIMIT: 11  // Should always be the last one.
+};
+
+/**
  * @enum {number}
  */
 var HistoryRange = {
   ALL_TIME: 0,
   WEEK: 1,
   MONTH: 2
 };