TextureMapperShaderProgram should be able to perform colorspace conversions while sampling a source texture. This will avoid swizzling color components in the CPU.
Created attachment 311586 [details] Patch
Seems that the GTK EWS was not in a good mood, but the patch builds.
Comment on attachment 311586 [details] Patch Clearing flags on attachment: 311586 Committed r217706: <http://trac.webkit.org/changeset/217706>
All reviewed patches have been landed. Closing bug.