Add storage on the surface for its last render task

Let's land this and see if it gets us back to baseline on the
lastRenderTask regression from the bug. If it doesn't, we'll revert it
since the extra complexity won't have been worth it.

Bug: skia:10372
Change-Id: I9d5ae93435b833d575afdc7f219dc8e7c453c92b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297836
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Adlai Holler <adlai@google.com>
9 files changed