> Fix scaling of tiled SVG backgrounds on high-dpi displays
> Reviewed by Dirk Schulze.
> This patch fixes the scaling of SVG when used for drawing patterns. Tiled/patterend SVG
> images are first drawn into an image buffer and then the image buffer is used to stamp
> out tiles. Because it is a raster source, the size of the image buffer needs to
> be scaled to the final resolution of the device. After scaling the image buffer, the
> source rect and pattern transforms need to be adjusted so they align in device pixel
> coordinates. This adjustment was not done before this patch, causing pixelated rendering.
> Additionally, a FIXME has been added due to webkit.org/b/110065 and the image buffer
> has been manually scaled (using "zoomedAndScaledContainerRect") instead of relying
> on the ImageBuffer's resolutionScale parameter.
> Test: svg/as-background-image/tiled-background-image.html
> * svg/graphics/SVGImage.cpp:
> Note that fixing the FIXME does not change that the source rect and transform need
> to be adjusted for page scale.
> * svg/as-background-image/tiled-background-image-expected.html: Added.
> * svg/as-background-image/tiled-background-image.html: Added.