rm pow2 arg to GrDirectContext::ComputeImagesize

Bug: skia:11208
Change-Id: I573be306e168adbd1c521626b2d1e4a303f8d5d9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/368621
Auto-Submit: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
3 files changed