[MD History] Add UMA stats for switching views and the CBD button.

chrome/browser/resources/md_history/browser_service.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.
 
 /**
  * @fileoverview Defines a singleton object, md_history.BrowserService, which
  * provides access to chrome.send APIs.
  */
 
 cr.define('md_history', function() {
@@ skipping 63 matching lines @@
      */
     deleteForeignSession: function(sessionTag) {
       chrome.send('deleteForeignSession', [sessionTag]);
     },
 
     openClearBrowsingData: function() {
       chrome.send('clearBrowsingData');
     },
 
     /**
+     * @param {string} histogram
+     * @param {number} value
+     * @param {number} max
+     */
+    recordHistogram: function(histogram, value, max) {
+      chrome.send('metricsHandler:recordInHistogram', [histogram, value, max]);
+    },
+
+    /**
     * Record an action in UMA.
     * @param {string} actionDesc The name of the action to be logged.
     */
     recordAction: function(actionDesc) {
       chrome.send('metricsHandler:recordAction', [actionDesc]);
     },
 
     /**
      * @param {boolean} successful
      * @private
@@ skipping 26 matching lines @@
   md_history.BrowserService.getInstance().resolveDelete_(true);
 }
 
 /**
  * Called by the history backend when the deletion failed.
  */
 function deleteFailed() {
   md_history.BrowserService.getInstance().resolveDelete_(false);
 }