Reviewed by Eric Seidel.

        Stop instantiating legacy editing positions in DeleteSelectionCommand, IndentOudentCommand,
        InsertLineBreakCommand, InsertListCOmmand.cpp, InsertParagraphSeparatorCommand, and htmlediting.cpp
        https://bugs.webkit.org/show_bug.cgi?id=52644

        This is a cleanup to stop instantiating legacy editing positions in the following tests.
        firstDeepEditingPositionForNode and lastDeepEditingPositionForNode in htmlediting.h are not updated
        because doing so requires significant code changes. They are tracked on the bug 52642.

        * editing/DeleteSelectionCommand.cpp:
        (WebCore::DeleteSelectionCommand::initializeStartEnd):
        (WebCore::updatePositionForNodeRemoval):
        (WebCore::DeleteSelectionCommand::removeNode):
        (WebCore::updatePositionForTextRemoval):
        (WebCore::DeleteSelectionCommand::handleGeneralDelete):
        * editing/IndentOutdentCommand.cpp:
        (WebCore::IndentOutdentCommand::outdentParagraph):
        * editing/InsertLineBreakCommand.cpp:
        (WebCore::InsertLineBreakCommand::doApply):
        * editing/InsertListCommand.cpp:
        (WebCore::InsertListCommand::doApplyForSingleParagraph):
        (WebCore::InsertListCommand::unlistifyParagraph):
        (WebCore::InsertListCommand::listifyParagraph):
        * editing/InsertParagraphSeparatorCommand.cpp:
        (WebCore::InsertParagraphSeparatorCommand::doApply):
        * editing/htmlediting.cpp:
        (WebCore::enclosingBlock):
        (WebCore::enclosingList):
        (WebCore::enclosingListChild):
        (WebCore::indexForVisiblePosition):
        (WebCore::isNodeVisiblyContainedWithin):
        (WebCore::avoidIntersectionWithNode):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@76057 268f45cc-cd09-0410-ab3c-d52691b4dbfc