Selection follows focus/activedescendant in single selection containers

third_party/WebKit/LayoutTests/accessibility/listbox-focus.html

Index: third_party/WebKit/LayoutTests/accessibility/listbox-focus.html
diff --git a/third_party/WebKit/LayoutTests/accessibility/listbox-focus.html b/third_party/WebKit/LayoutTests/accessibility/listbox-focus.html
index d0b7d0db00bcc770cf1b2f4421f7ee2cc670bc38..017a2c8d3db1e32e30e5aab67cc11b7ed2fd55d6 100644
--- a/third_party/WebKit/LayoutTests/accessibility/listbox-focus.html
+++ b/third_party/WebKit/LayoutTests/accessibility/listbox-focus.html
@@ -5,6 +5,7 @@
   <option id="item0">Alicia</option>
   <option id="item1">Peter</option>
   <option id="item2">Kalinda</option>
+  <option id="item3" disabled>Frank</option>
 </select>
 <script>
 async_test(function(t)
@@ -37,4 +38,18 @@ async_test(function(t)
         listbox.selectedIndex = 1;
     }, 0);
 }, "menu list fires correct events when active index changes.");
+
+function axElementById(id) {
+    return accessibilityController.accessibleElementById(id);
+}
+
+test(function(t) {
+    var axOption = axElementById("item2");
+    assert_equals(axOption.isFocusable, true);
+}, "Listbox option is focusable");
+
+test(function(t) {
+    var axOption = axElementById("item3");
+    assert_equals(axOption.isFocusable, false);
+}, "Disabled listbox option is not focusable");
 </script>