Reviewed by Chris

    Reviewed by Chris

        Fix for this bug:

        <rdar://problem/3820349> REGRESSION (Mail): select all, delete does not always delete everything

        * khtml/editing/htmlediting.cpp:
        (khtml::DeleteSelectionCommand::startPositionForDelete): New helper that determines when to
        expand the selection outwards when the selection is on the visible boundary of a root
        editable element. This fixes the bug. Note that this function also contains a little code
        I factored out of doApply: it also takes care of adjusting the selection in the smart delete case.
        (khtml::DeleteSelectionCommand::endPositionForDelete): Ditto.
        (khtml::DeleteSelectionCommand::doApply): Call new helpers. Refactored out the code as described.
        * khtml/editing/htmlediting.h: Declare new helpers.
        * layout-tests/editing/deleting/delete-select-all-001-expected.txt: Added.
        * layout-tests/editing/deleting/delete-select-all-001.html: Added.
        * layout-tests/editing/deleting/delete-select-all-002-expected.txt: Added.
        * layout-tests/editing/deleting/delete-select-all-002.html: Added.
        * layout-tests/editing/deleting/delete-select-all-003-expected.txt: Added.
        * layout-tests/editing/deleting/delete-select-all-003.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@7890 268f45cc-cd09-0410-ab3c-d52691b4dbfc