Refactoring: Move m_mayDisplaySeamlesslyWithParent down to Document

The member is used only in Document, thus no reason to
stay in SecurityContext.

TEST=none
BUG=none
R=haraken@chromium.org, abarth, haraken, hayato

Review URL: https://codereview.chromium.org/27615003

git-svn-id: svn://svn.chromium.org/blink/trunk@159829 bbb929c8-8fbe-4397-9dbb-9b2b20218538
PassRefPtr<Event> Document::createEvent(const String& eventType, ExceptionState& es)
{
    RefPtr<Event> event = EventFactory::create(eventType);
    if (event)
        return event.release();

    es.throwUninformativeAndGenericDOMException(NotSupportedError);
    return 0;
}

PassRefPtr<Event> Document::createEvent(const String& eventType, ExceptionState& es)
{
    RefPtr<Event> event = EventFactory::create(eventType);
    if (event)
        return event.release();

    es.throwUninformativeAndGenericDOMException(NotSupportedError);
    return 0;
}
