Various fixes for aria-activedescendant.

third_party/WebKit/Source/modules/accessibility/AXListBoxOption.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 106 matching lines @@
         return true;
 
     if (accessibilityIsIgnoredByDefault(ignoredReasons))
         return true;
 
     return false;
 }
 
 bool AXListBoxOption::canSetSelectedAttribute() const
 {
+    if (ancestorExposesActiveDescendant())

[dmazzoni, 2016/03/31 05:48:30]

This shouldn't be before some of the other checks, for example we should first
check if it's disabled.

+        return true;
+
     if (!isHTMLOptionElement(getNode()))
         return false;
 
     if (toHTMLOptionElement(getNode())->isDisabledFormControl())
         return false;
 
     HTMLSelectElement* selectElement = listBoxOptionParentNode();
     if (selectElement && selectElement->isDisabledFormControl())
         return false;
 
@@ skipping 65 matching lines @@
     unsigned length = listItems.size();
     for (unsigned i = 0; i < length; i++) {
         if (listItems[i] == getNode())
             return i;
     }
 
     return -1;
 }
 
 } // namespace blink