Reviewed by Maciej.

    Reviewed by Maciej.

        <rdar://problem/4048506> Deleting from beginning of editable div deletes other document elements

        Also changed WebKit.

        * khtml/editing/visible_units.h:
        * khtml/editing/visible_units.cpp:
        (khtml::startOfEditableContent):
        (khtml::endOfEditableContent):
        (khtml::inSameEditableContent):
        (khtml::isStartOfEditableContent):
        (khtml::isEndOfEditableContent):
        New.

        * kwq/WebCoreBridge.h:
        * kwq/WebCoreBridge.mm:
        (-[WebCoreBridge canDeleteRange:]):
        New.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8905 268f45cc-cd09-0410-ab3c-d52691b4dbfc