Bug with baseOffset and extentOffset in selections (for writely.com)
        <rdar://problem/4259818>
        selection object incorrect after double-clicking a word

        Reviewed by harrison

        Changed the Selection object's anchor/focus properties to match
        Mozilla's Selection object API, added getRangeAt and outlined the
        rest of the API.
        Cleaned up the JS Selection object (to do less work in the DOM binding).
        Added an updateLayout call to VisiblePosition::init and removed some
        updateLayout calls from other parts of the editing code.

        Added layout tests:
        * editing/selection/getRangeAt.html
        * editing/selection/anchor-focus1.html
        * editing/selection/anchor-focus2.html
        * editing/selection/anchor-focus3.html
        Updated expected results:
        * editing/selection/unrendered-001-expected.txt

        * khtml/ecma/kjs_window.cpp:
        (KJS::Selection::getValueProperty):
        (KJS::Selection::toString):
        (KJS::SelectionFunc::callAsFunction):
        * khtml/ecma/kjs_window.h:
        (KJS::Selection::):
        * khtml/editing/SelectionController.cpp:
        (khtml::SelectionController::modify):
        (khtml::SelectionController::type):
        (khtml::SelectionController::toString):
        (khtml::SelectionController::getRangeAt):
        (khtml::SelectionController::setBaseAndExtent):
        (khtml::SelectionController::setPosition):
        (khtml::SelectionController::collapse):
        (khtml::SelectionController::collapseToEnd):
        (khtml::SelectionController::collapseToStart):
        (khtml::SelectionController::empty):
        (khtml::SelectionController::extend):
        (khtml::SelectionController::validate):
        * khtml/editing/SelectionController.h:
        (khtml::SelectionController::part):
        (khtml::SelectionController::baseNode):
        (khtml::SelectionController::extentNode):
        (khtml::SelectionController::baseOffset):
        (khtml::SelectionController::extentOffset):
        (khtml::SelectionController::anchorNode):
        (khtml::SelectionController::anchorOffset):
        (khtml::SelectionController::focusNode):
        (khtml::SelectionController::focusOffset):
        (khtml::SelectionController::isCollapsed):
        * khtml/editing/visible_position.cpp:
        (khtml::VisiblePosition::init):
        (khtml::VisiblePosition::isCandidate):
        * khtml/khtml_part.cpp:
        (KHTMLPart::handleMousePressEventSingleClick):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@11857 268f45cc-cd09-0410-ab3c-d52691b4dbfc