Disabled select element should not fire onchange event.

Source/core/rendering/RenderListBox.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  *               2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * 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. 
@@ skipping 544 matching lines @@
         return offset + rows - 1;
     
     return listIndexAtOffset(positionOffset);
 }
 
 void RenderListBox::autoscroll(const IntPoint&)
 {
     IntPoint pos = frame()->view()->windowToContents(frame()->eventHandler()->lastKnownMousePosition());
 
     int endIndex = scrollToward(pos);
+    if (selectElement()->isDisabledFormControl())
+        return;
+
     if (endIndex >= 0) {
         HTMLSelectElement* select = selectElement();
         m_inAutoscroll = true;
 
         if (!select->multiple())
             select->setActiveSelectionAnchorIndex(endIndex);
 
         select->setActiveSelectionEndIndex(endIndex);
         select->updateListBoxSelection(!select->multiple());
         m_inAutoscroll = false;
     }
 }
 
 void RenderListBox::stopAutoscroll()
 {
+    if (selectElement()->isDisabledFormControl())
+        return;
+
     selectElement()->listBoxOnChange();
 }
 
 bool RenderListBox::scrollToRevealElementAtListIndex(int index)
 {
     if (index < 0 || index >= numItems() || listIndexIsVisible(index))
         return false;
 
     int newOffset;
     if (index < m_indexOffset)
@@ skipping 289 matching lines @@
 
     if (m_vBar)
         m_vBar->styleChanged();
 
     // Force an update since we know the scrollbars have changed things.
     if (document()->hasAnnotatedRegions())
         document()->setAnnotatedRegionsDirty(true);
 }
 
 } // namespace WebCore