Sketch in gni file lists for moved colorfilter files

I'm planning on moving ColorFilters to src/effects/colorfilters
and this will let me break them up into more granular filegroups.

This is particularly necessary to deal with the ones that require
SkSL so we can have a no-op version of them if SkSL is disabled.

Change-Id: Ic74a511cb99a87f021bd8a3096372e9e789fc697
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/705223
Reviewed-by: Ben Wagner <bungeman@google.com>
2 files changed