[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 {Array} args
+     */
+    recordAction: function(args) {
+      chrome.send('metricsHandler:recordAction', args);

[tsergeant, 2016/08/15 07:05:17]

Replace args with a single argument for the action name and package it into an
array in the chrome.send call.

(We know exactly what the recordAction call expects, so there's no reason not to
expand it out and get proper type checking).

[calamity, 2016/08/17 03:15:28]

Done.

+    },
+
+    /**
+     * @param {Array} args
+     */
+    recordHistogram: function(args) {
+      chrome.send('metricsHandler:recordInHistogram', args);

[tsergeant, 2016/08/15 07:05:17]

As above, use specific arguments here rather than an array.

[calamity, 2016/08/17 03:15:29]

Done.

+    },
+
+    /**
      * @param {boolean} successful
      * @private
      */
     resolveDelete_: function(successful) {
       if (this.pendingDeleteItems_ == null ||
           this.pendingDeletePromise_ == null) {
         return;
       }
 
       if (successful)
@@ skipping 18 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);
 }