Reviewed by Dan Bernstein.

        Pixel cracks when using background image sprite on transformed element at certain scales.
        https://bugs.webkit.org/show_bug.cgi?id=47868

        * fast/images/pixel-crack-image-background-webkit-transform-scale.html: Added.
        * fast/images/resources/pixel-crack-image-background-webkit-transform-scale.png: Added.
        * platform/mac/fast/images/pixel-crack-image-background-webkit-transform-scale-expected.checksum: Added.
        * platform/mac/fast/images/pixel-crack-image-background-webkit-transform-scale-expected.png: Added.
        * platform/mac/fast/images/pixel-crack-image-background-webkit-transform-scale-expected.txt: Added.
2010-10-19  Yongjun Zhang  <yongjun_zhang@apple.com>

        Reviewed by Dan Bernstein.

        Pixel cracks when using background image sprite on transformed element at certain scales.
        https://bugs.webkit.org/show_bug.cgi?id=47868

        The pixel bleeding happens when the current context has scale and interpolation is kCGInterpolationHigh
        or kCGInterpolationDefault.  If the source rect size is smaller than the intrinsic image size,  some
        pixels outside of the clip rect will also be used to interpolate the color value for clip edges, which
        results in unwanted thin lines around the painted area.  We need to use sub-image patch to get rid of
        the artifacts in this case.

        Test: fast/images/pixel-crack-image-background-webkit-transform-scale.html

        * platform/graphics/cg/ImageCG.cpp:
        (WebCore::BitmapImage::draw):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@70118 268f45cc-cd09-0410-ab3c-d52691b4dbfc