GitLab

Writes separate sections of allocator types for the OOP memory log.
Sone refactoring in support of this.

Adds tests for allocator splits and context information.

Bug: 763173
Change-Id: I81aeae226075b221d5b0b944fe74980557ffce32
Reviewed-on: https://chromium-review.googlesource.com/664083
Commit-Queue: Brett Wilson <brettw@chromium.org>
Reviewed-by: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501674}