Reland "pack SkTArray"

This is a reland of b3c42efd25b9a139dcdcf305f0d396120b4054f2
with a few more signed/unsigned mismatches fixed up.

Original change's description:
> pack SkTArray
>
> Same idea as http://review.skia.org/325857; I just wanted to feel out
> the options myself. A couple key ideas:
>
>     Prefer SkTo32() to separate range assertions and casts.
>
>     Keep using int indices, counting to this->count() where
>     fCount would have warned about signed/unsigned mismatch.
>
> I've kept new comments and assertions to minimum.  In the end we won't
> change the max size of SkTArray, and I don't see much need to call out
> how much it hasn't changed.  Reading back over the accumulated changes,
> I don't really see much that's newly error-prone.
>
> Change-Id: I86a8a161b9ae44f24fc25093741945b75fbfa770
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/326106
> Commit-Queue: Mike Klein <mtklein@google.com>
> Reviewed-by: John Stiles <johnstiles@google.com>

Change-Id: I04d928ecc185fb5c7b9d32f60e94df9f8d137898
Cq-Include-Trybots: luci.skia.skia.primary:Build-Win-MSVC-x86_64-Debug-Vulkan,Build-Win-MSVC-x86-Debug
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/326297
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
1 file changed