Add UMA stats for user settings

chrome/browser/resources/options/browser_options.js

 // Copyright (c) 2012 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.
 
 cr.define('options', function() {
   var OptionsPage = options.OptionsPage;
   var ArrayDataModel = cr.ui.ArrayDataModel;
   var RepeatingButton = cr.ui.RepeatingButton;
   var HotwordSearchSettingIndicator = options.HotwordSearchSettingIndicator;
 
@@ skipping 82 matching lines @@
           // If the link was focused (i.e., it was activated using the keyboard)
           // and it was used to show the section (rather than hiding it), focus
           // the first element in the container.
           if (document.activeElement === $('advanced-settings-expander') &&
                   $('advanced-settings').style.height === '') {
             var focusElement = $('advanced-settings-container').querySelector(
                 'button, input, list, select, a[href]');
             if (focusElement)
               focusElement.focus();
           }
+
+          chrome.send('coreOptionsUserMetricsAction',
+                      ['Options_ShowAdvancedSettings']);

[michaelpg, 2014/06/13 23:15:43]

Worth noting that this count will report up to 2x as many "show advanced
settings" actions as there actually are because users can hit "hide settings"
after "show settings". The actual factor is probably closer to 1.01, but could
you use the test in 97 to check whether they're being shown or hidden?

We probably only care about when they're being shown.

[stevenjb, 2014/06/16 21:58:10]

Done.

         };
       } else {
         $('advanced-settings-expander').hidden = true;
         $('advanced-settings').hidden = true;
       }
 
       $('advanced-settings').addEventListener('webkitTransitionEnd',
           this.updateAdvancedSettingsExpander_.bind(this));
 
       if (cr.isChromeOS) {
@@ skipping 1732 matching lines @@
     BrowserOptions.getLoggedInUsername = function() {
       return BrowserOptions.getInstance().username_;
     };
   }
 
   // Export
   return {
     BrowserOptions: BrowserOptions
   };
 });