Reland "Update the SkSL pool interface to take an allocation size."

This is a reland of 22ef2257c8624e2383876c6fbb641162fe520228

This reland fixes an issue with ExternalValue nodes on 32-bit builds;
these should never be pooled, because we can't control their lifetimes.

Original change's description:
> Update the SkSL pool interface to take an allocation size.
>
> Since our end goal no longer has all IRNodes ending up as the exact same
> size in memory, it makes sense for the allocator function to take in a
> desired size. This also opens the door to separate "small" and "large"
> pools, if we want to add pooling support for large but semi-common
> things like Variables.
>
> Change-Id: If3dbe31588adeedede327c5967c344a19507b6fa
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/329961
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>
> Auto-Submit: John Stiles <johnstiles@google.com>

Change-Id: If701ae4a5e18b66d4138bc09c9c8dc1a60579c90
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/330105
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
4 files changed