Add support for indirect-stores to Raster Pipeline trace_var.

This will allow debug variable-traces to reuse the indirect-offset
calculations that dynamic-offset lvalues already use. It will be
wired up to SkRP codegen in a followup.

Change-Id: I38b2dd92cb9ccad36d6a26e7ba96763a7af34e7f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/663278
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
4 files changed