This library comes from Chromium's base, and is useful for many use
cases in ANGLE. It can replace the custom MRU code we use in the
RenderStateCache. It will also be useful for implementing a program
binary cache.

BUG=angleproject:2044

Change-Id: Iba166fe380d7ed4e3123428b0227b9d299f756d1
Reviewed-on: https://chromium-review.googlesource.com/516384
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>