Stops using SYSTEM_STATE_INDETERMINATE as it makes radio buttons appear to have a mixed state.

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

 /*
  * Copyright (C) 2008, 2009, 2011 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 891 matching lines @@
     case MenuListPopupRole:
         // FIXME: Implement.
         return String();
     default:
         return emptyString();
     }
 }
 
 AccessibilityButtonState AXObject::checkboxOrRadioValue() const
 {
-    // If this is a real checkbox or radio button, AXLayoutObject will handle.
+    // If this is a real checkbox or radio button, AXNodeObject will handle it.
     // If it's an ARIA checkbox or radio, the aria-checked attribute should be used.
-
     const AtomicString& result = getAttribute(aria_checkedAttr);
     if (equalIgnoringCase(result, "true"))
         return ButtonStateOn;
     if (equalIgnoringCase(result, "mixed")) {
+        // Only checkboxes should support the mixed state.
         AccessibilityRole role = ariaRoleAttribute();
-        if (role == RadioButtonRole || role == MenuItemRadioRole || role == SwitchRole)
-            return ButtonStateOff;
-        return ButtonStateMixed;
+        if (role == CheckBoxRole || role == MenuItemCheckBoxRole)
+            return ButtonStateMixed;
     }
 
     return ButtonStateOff;
 }
 
 bool AXObject::isMultiline() const
 {
     Node* node = this->node();
     if (!node)
         return false;
@@ skipping 748 matching lines @@
 
 DEFINE_TRACE(AXObject)
 {
     visitor->trace(m_children);
     visitor->trace(m_parent);
     visitor->trace(m_cachedLiveRegionRoot);
     visitor->trace(m_axObjectCache);
 }
 
 } // namespace blink