Split off memory metrics for network service from general utility.

Based almost entirely off Matt Menke's
https://chromium-review.googlesource.com/c/chromium/src/+/1546318

Bug: 947573
Change-Id: I7571b33cd7e5e3ea4bde4768727d0932e391f6f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1551181
Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Maks Orlovich <morlovich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657388}
3 files changed