Currently layerTreeAsText doesn't provide any info on how blend mode is propagated to GraphicsLayers. There are some cases we should check if blend mode is correctly set, for example, when the blending layer has an ancestor clipping layer.
Created attachment 226910 [details]
Don't forget to proper guard the blending changes with
// blending code
Created attachment 226911 [details]
Comment on attachment 226911 [details]
Clearing flags on attachment: 226911
Committed r165804: <http://trac.webkit.org/changeset/165804>
All reviewed patches have been landed. Closing bug.