Reviewed by Adele.

    Reviewed by Adele.

        - fixed <rdar://problem/4006596> REGRESSION (183-184): crash in DOM::DocumentImpl::setFocusNode(DOM::NodeImpl*)

        * khtml/xml/dom_docimpl.cpp:
        (widgetForNode): Added helper.
        (DocumentImpl::setFocusNode): Re-get the widget for the node after calling updateLayout.
        The updateLayout can destroy the old widget, so we can't keep a stale widget pointer around.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8662 268f45cc-cd09-0410-ab3c-d52691b4dbfc