Reviewed by Ken and Darin.

    Reviewed by Ken and Darin.

        <rdar://problem/3856215> Cannot remove bold from the beginning of a message

        Problem is that KHTMLPart::computeAndSetTypingStyle always looked upstream
        for the existing style, but in this case (hitting cmd-B with caret at top of
        file) there is nothing upstream.  Changed this to use the VisiblePosition
        deepEquivalent instead.

        * khtml/khtml_part.cpp:
        (KHTMLPart::computeAndSetTypingStyle):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8056 268f45cc-cd09-0410-ab3c-d52691b4dbfc