SkFixedAlloc

Looking at SkSmallAlloc hasn't left me terribly impressed.  I think we can replace it with something a lot simpler to work with.

That simpler thing's core would be something like SkFixedAlloc, which allocates objects out of a fixed sized buffer, and cleans them up when done.

If needed, we can wrap that with logic to try to allocate out of an SkFixedAlloc, falling back on mallc() when exhausted.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4658

Change-Id: I8d94156ddf98802e42ec0890cff0f06b21f073b0
Reviewed-on: https://skia-review.googlesource.com/4658
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
5 files changed