- Avoids allocations when adding entries to the global pool
- Avoids taking the lock when not working on the global pool

Bug: 
Change-Id: I380b91d8fed2cab95fd84c4a3f4144cc8d6de86d
Reviewed-on: https://chromium-review.googlesource.com/582691
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46836}