Fix for bugs 9000 and 10606. Add code to suppress painting when

    Fix for bugs 9000 and 10606.  Add code to suppress painting when
        a FOUC situation would otherwise occur.  There will still typically be
        a flash to white, but at least the wrong content won't show.

        Reviewed by darin

        * dom/Document.cpp:
        (WebCore::Document::Document):
        (WebCore::Document::updateLayoutIgnorePendingStylesheets):
        (WebCore::Document::preferredStylesheetSet):
        (WebCore::Document::selectedStylesheetSet):
        (WebCore::Document::setSelectedStylesheetSet):
        (WebCore::Document::stylesheetLoaded):
        (WebCore::Document::updateStyleSelector):
        * dom/Document.h:
        (WebCore::Document::haveStylesheetsLoaded):
        * rendering/RenderBlock.cpp:
        (WebCore::RenderBlock::paintChildren):
        * rendering/RenderLayer.cpp:
        (WebCore::RenderLayer::paintLayer):
        (WebCore::isSubframe):
        (WebCore::RenderLayer::hitTest):
        * rendering/RenderView.cpp:
        (WebCore::RenderView::repaintViewRectangle):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@16129 268f45cc-cd09-0410-ab3c-d52691b4dbfc