Reviewed by Adam Barth.

        Fix </optgroup> in "in select" mode
        https://bugs.webkit.org/show_bug.cgi?id=41733

        * html5lib/runner-expected-html5.txt:
2010-07-06  Eric Seidel  <eric@webkit.org>

        Reviewed by Adam Barth.

        Fix </optgroup> in "in select" mode
        https://bugs.webkit.org/show_bug.cgi?id=41733

        I had to add a oneBelowTop() accessor.
        I added some ASSERTs after looking at the fragment case
        documentation.  I'm now convinced that top() and oneBeforeTop()
        should never be NULL, so we just ASSERT they aren't.

        This is a very obscure corner of the HTML spec, but at least
        we have a test for it.  This makes one more html5lib test pass.

        * html/HTMLConstructionSite.h:
        (WebCore::HTMLConstructionSite::oneBelowTop):
        * html/HTMLElementStack.cpp:
        (WebCore::HTMLElementStack::topRecord):
        (WebCore::HTMLElementStack::top):
        (WebCore::HTMLElementStack::oneBelowTop):
        * html/HTMLElementStack.h:
        * html/HTMLTreeBuilder.cpp:
        (WebCore::HTMLTreeBuilder::processEndTag):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@62618 268f45cc-cd09-0410-ab3c-d52691b4dbfc