Use scopes to attach and detach SkSL memory pools.

This makes pool handling easier and less error-prone.

Change-Id: I63a6b63a9ff45431921bfbbc56d537a25e2770c8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/437337
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
3 files changed