Reviewed by oliver
        
        <rdar://problem/5120591> Crash when creating a link in Leopard wiki server

        * editing/execCommand/5120591-expected.checksum: Added.
        * editing/execCommand/5120591-expected.png: Added.
        * editing/execCommand/5120591-expected.txt: Added.
        * editing/execCommand/5120591.html: Added.

WebCore:

        Reviewed by oliver

        <rdar://problem/5120591> 
        Crash when creating a link in Leopard wiki server

        * editing/CreateLinkCommand.cpp:
        (WebCore::CreateLinkCommand::doApply): Use a RefPtr,
        setting the anchor's href can destroy it if there is
        an ancestor with a subtree modified event listener.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@21123 268f45cc-cd09-0410-ab3c-d52691b4dbfc