Reviewed by Kent Tamura.

        https://bugs.webkit.org/show_bug.cgi?id=43960
        [Chromium] styled scroll bar on the window is painted badly.

        * platform/chromium/test_expectations.txt: Skips at this time and will rebaseline shortly.
        * platform/mac/Skipped: Mac doesn't suffer from the problem.
        * scrollbars/custom-scrollbar-with-incomplete-style.html: Added.
2010-08-13  MORITA Hajime  <morrita@google.com>

        Reviewed by Kent Tamura.

        https://bugs.webkit.org/show_bug.cgi?id=43960
        [Chromium] styled scroll bar on the window is painted badly.

        WebKit assumes outermost scrollbar always painted.
        So force their style to have the  background color if it isn't
        given by the stylesheet.

        Test: scrollbars/custom-scrollbar-with-incomplete-style.html

        * rendering/RenderObject.h:
        (WebCore::RenderObject::hasBackground): Extracted body to RenderStyle for sharing.
        * rendering/RenderScrollbar.cpp:
        (WebCore::RenderScrollbar::getScrollbarPseudoStyle): Added the workaround as mentioned above.
        * rendering/RenderScrollbar.h:
        * rendering/style/RenderStyle.h:
        (WebCore::InheritedFlags::hasBackground): Extracted from RenderObject.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@66372 268f45cc-cd09-0410-ab3c-d52691b4dbfc