Type usage improvements in GrTextureProducer classes

Make better use of SkISize and GrImageInfo.

Change-Id: Ie3c9f16d7db05e6527baf1aae4607d74d020ee49
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/250577
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
16 files changed