Swap uniform pointers in SkFilterColorProgram, improve comment

An upcoming CL will need to refer to the (now) first uniform IDs while
processing the second set, so arranging them like this makes more sense.
Landing this reordering first, to avoid making the new CL even more
confusing.

Change-Id: If19933edbabe840dd427525e5fceac8cd7fb1714
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/420120
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
1 file changed