Reviewed by Dimitri Glazkov.

        REGRESSION(r74228-75294): removing nodes is 200+ times slower when selection is inside a shadow DOM
        https://bugs.webkit.org/show_bug.cgi?id=57061

        The bug was caused by Range::compareNode's incorrectly returning NODE_INSIDE when the selection is inside
        a shadow DOM and the node is outside of the shadow DOM. This caused respondToNodeModification to call
        RenderView::clearSelection every time a node is removed when selection is in a shadow DOM and resulted in
        a significant performance regression.

        Fixed Ranged::compareNode by making Range::compareBoundaryPoints throw a WRONG_DOCUMENT_ERR when there are
        no common ancestors between containerA and containerB. This will force compareNode to also throw an exception
        and prevents respondToNodeModification from clearing selection.

        No new tests because this is a performance improvement and the fix in Range cannot be tested since shadow DOM
        isn't exposed to JavaScript.

        * dom/Range.cpp:
        (WebCore::Range::setStart): Calls compareBoundaryPoints; since we ensures that the root container noes of
        start and end nodes are same, we should never get an exception from compareBoundaryPoints.
        (WebCore::Range::setEnd): Ditto.
        (WebCore::Range::isPointInRange): Calls compareBoundaryPoints; returns false when compareBoundaryPoints
        throws an exception.
        (WebCore::Range::comparePoint): Calls compareBoundaryPoints; exit early when an exception is thrown by
        compareBoundaryPoints.
        (WebCore::Range::compareBoundaryPoints): Throws an exception when two containers do not have a common ancestor.
        (WebCore::Range::boundaryPointsValid): Calls compareBoundaryPoints and checks that it didn't throw an exception.
        * dom/Range.h:
        * editing/SelectionController.cpp:
        (WebCore::SelectionController::respondToNodeModification):
        * editing/htmlediting.cpp:
        (WebCore::comparePositions): Calls compareBoundaryPoints.
        * editing/markup.cpp:
        (WebCore::createMarkup): Calls compareBoundaryPoints; since startNode and pastEnd are both in the same document
        and neither are in a shadow DOM, it should never throw an exception.
        * page/DOMSelection.cpp:
        (WebCore::DOMSelection::containsNode): Calls compareBoundaryPoints; node is fully selected only if no exception
        was thrown.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@84265 268f45cc-cd09-0410-ab3c-d52691b4dbfc