Add accessibility settings metrics

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 478 matching lines @@
 
       // Accessibility section (CrOS only).
       if (cr.isChromeOS) {
         var updateAccessibilitySettingsButton = function() {
           $('accessibility-settings').hidden =
               !($('accessibility-spoken-feedback-check').checked);
         };
         Preferences.getInstance().addEventListener(
             'settings.accessibility',
             updateAccessibilitySettingsButton);
-        $('accessibility-settings-button').onclick = function(event) {
+        $('accessibility-learn-more').onclick = function(unused_event) {
+          window.open(loadTimeData.getString('accessibilityLearnMoreURL'));
+          chrome.send('coreOptionsUserMetricsAction',
+                      ['Options_AccessibilityLearnMore']);
+        };
+        $('accessibility-settings-button').onclick = function(unused_event) {
           window.open(loadTimeData.getString('accessibilitySettingsURL'));
         };
-        $('accessibility-spoken-feedback-check').onchange = function(event) {
+        $('accessibility-spoken-feedback-check').onchange = function(
+            unused_event) {
           chrome.send('spokenFeedbackChange',
                       [$('accessibility-spoken-feedback-check').checked]);
           updateAccessibilitySettingsButton();
         };
         updateAccessibilitySettingsButton();
 
-        $('accessibility-high-contrast-check').onchange = function(event) {
+        $('accessibility-high-contrast-check').onchange = function(
+            unused_event) {
           chrome.send('highContrastChange',
                       [$('accessibility-high-contrast-check').checked]);
         };
 
         var updateDelayDropdown = function() {
           $('accessibility-autoclick-dropdown').disabled =
               !$('accessibility-autoclick-check').checked;
         };
         Preferences.getInstance().addEventListener(
             $('accessibility-autoclick-check').getAttribute('pref'),
@@ skipping 1325 matching lines @@
     BrowserOptions.getLoggedInUsername = function() {
       return BrowserOptions.getInstance().username_;
     };
   }
 
   // Export
   return {
     BrowserOptions: BrowserOptions
   };
 });