Reviewed by Hyatt.

        - pixel test for http://bugzilla.opendarwin.org/show_bug.cgi?id=4334
          REGRESSION: Flickering when css-hover should change opacity on floating elements

        * fast/block/float/nopaint-after-layer-destruction-expected.checksum: Added.
        * fast/block/float/nopaint-after-layer-destruction-expected.png: Added.
        * fast/block/float/nopaint-after-layer-destruction-expected.txt: Added.
        * fast/block/float/nopaint-after-layer-destruction.html: Added.

WebCore:

        Reviewed by Hyatt (concept) and Darin (some coding details).

        - fix http://bugzilla.opendarwin.org/show_bug.cgi?id=4334
          REGRESSION: Flickering when css-hover should change opacity on floating elements

        Pixel test: fast/block/float/nopaint-after-layer-destruction.html

        * rendering/RenderBlock.cpp:
        (WebCore::RenderBlock::setPaintsFloatingObject): Added. Changes the noPaint flag
        in the block's FloatingObject for the given float and calls setChildNeedsLayout.
        * rendering/RenderBlock.h:
        * rendering/RenderBox.cpp:
        (WebCore::blockThatPaintsFloat): Added this helper function.
        (WebCore::RenderBox::setStyle): Added. Calls to setPaintsFloatingObject when a float
        gains or loses its layer.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@14759 268f45cc-cd09-0410-ab3c-d52691b4dbfc