options: Fix focus "Show advanced settings..." click focus regression.

chrome/browser/resources/options/browser_options.js

Index: chrome/browser/resources/options/browser_options.js
diff --git a/chrome/browser/resources/options/browser_options.js b/chrome/browser/resources/options/browser_options.js
index c92fa1df42bc7c5c4bc0e7ca50512076fd3a49ad..b8c0dd5776f67e23628108d78e49b3936b1b1c77 100644
--- a/chrome/browser/resources/options/browser_options.js
+++ b/chrome/browser/resources/options/browser_options.js
@@ -116,7 +116,7 @@ cr.define('options', function() {
       window.addEventListener('message', this.handleWindowMessage_.bind(this));
 
       if (loadTimeData.getBoolean('allowAdvancedSettings')) {
-        $('advanced-settings-expander').onclick = function() {
+        $('advanced-settings-expander').onclick = function(e) {
           var showAdvanced =
               BrowserOptions.shouldShowSection_($('advanced-settings'));
           if (showAdvanced) {
@@ -127,11 +127,10 @@ cr.define('options', function() {
               $('advanced-settings'),
               $('advanced-settings-container'));
 
-          // 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') &&

[Dan Beam, 2014/11/18 03:35:38]

mousedown can call .focus() so this wasn't particularly robust

-              showAdvanced) {
+          // If the click was triggered using the keyboard and it showed the
+          // section (rather than hiding it), focus the first element in the
+          // container.
+          if (!e.x && showAdvanced) {

[Dan Beam, 2014/11/18 03:35:37]

it's possible e.x != 0 in the future when pressing Enter
http://www.w3.org/TR/DOM-Level-3-Events/#click-synthesis

             var focusElement = $('advanced-settings-container').querySelector(
                 'button, input, list, select, a[href]');
             if (focusElement)