Revert "Remove ARC from tools lib."

This reverts commit 4c4c80fa12649e2512e4601d0a19f19f8907d6ca.

Reason for revert: Need to update Flutter with sk_cf_obj renaming.

Original change's description:
> Remove ARC from tools lib.
>
> Trying this in baby steps to manage leaks better.
>
> Change-Id: Id8597ba236c752bcbf1c7ec94f6c1021e636d547
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/372556
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Adlai Holler <adlai@google.com>

TBR=jvanverth@google.com,bsalomon@google.com,adlai@google.com

Change-Id: I7dc226d002184b80a1d8d2aee09d122d2e13d732
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/372680
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
13 files changed