Reviewed by Maciej, Darin.

    Reviewed by Maciej, Darin.

        <rdar://problem/4103339> VisiblePosition and PositionIterator iterators do not return positions in order

        * WebCore.pbproj/project.pbxproj:
        Removed dom_positioniterator.h and dom_positioniterator.cpp.

        * khtml/editing/htmlediting.cpp:
        Removed unused include of dom_positioniterator.h and "using" of PositionIterator.

        * khtml/editing/selection.cpp:
        Removed unused include of dom_positioniterator.h.

        * khtml/editing/visible_position.h:
        * khtml/editing/visible_position.cpp:
        (khtml::VisiblePosition::previousVisiblePosition):
        (khtml::VisiblePosition::nextVisiblePosition):
        (khtml::VisiblePosition::downstreamDeepEquivalent):
        Use Position::next(), Position::previous(), Position::atStart(), Position::atEnd() instead of duplicated code.

        * khtml/xml/dom_nodeimpl.h:
        * khtml/xml/dom_nodeimpl.cpp:
        (NodeImpl::maxDeepOffset):
        Added to support Position::next(), Position::previous(), Position::atStart(), Position::atEnd()

        * khtml/xml/dom_position.h:
        * khtml/xml/dom_position.cpp:
        (DOM::Position::previous):
        (DOM::Position::next):
        (DOM::Position::atStart):
        (DOM::Position::atEnd):
        Moved here, replacing VisiblePosition's duplicate and PositionIterator.  Fixed to
        return positions in order and not skip positions.

        (DOM::Position::previousCharacterPosition):
        (DOM::Position::nextCharacterPosition):
        Use Position::next(), Position::previous(), Position::atStart(), Position::atEnd() instead of PositionIterator.

        (DOM::isStreamer):
        (DOM::Position::upstream):
        (DOM::Position::downstream):
        Use Position::next(), Position::previous(), Position::atStart(), Position::atEnd() instead of PositionIterator.

        * khtml/xml/dom_positioniterator.cpp: Removed.
        * khtml/xml/dom_positioniterator.h: Removed.
        Removed in favor of Position::next(), Position::previous(), Position::atStart(), Position::atEnd()

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@9130 268f45cc-cd09-0410-ab3c-d52691b4dbfc