tracing: Add private footprint

tracing: Add private footprint

Private footprint is a cross-platform, consistent, validated measurement of the
amount of memory a process is using which is:
- private
- non-discardable
- anonymous [not backed by a file]
- Either resident, compressed, or swapped
This plumbs it through Tracing and adds it to the memory metric definitions.

BUG=chromium:737325
Review-Url: https://chromiumcodereview.appspot.com/3012213002
Committed: https://chromium.googlesource.com/external/github.com/catapult-project/catapult/+/b9a4b34443ef5b93696e0968b4b6884c074acc37

[hjd_google, 2017-09-12 17:11:08]

hjd@google.com changed reviewers:
+ benjhayden@chromium.org, hjd@google.com

[hjd_google, 2017-09-12 17:11:09]

ptal, thanks! :)

[benjhayden, 2017-09-12 17:40:48]

lgtm

[hjd_google, 2017-09-12 17:41:44]

The CQ bit was checked by hjd@google.com

[commit-bot: I haz the power, 2017-09-12 17:41:47]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-09-12 18:15:26]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1505238104600500, "parent_rev":
"521b014da0affb8eb18679144f5939193df53a5b", "commit_rev":
"b9a4b34443ef5b93696e0968b4b6884c074acc37"}

[commit-bot: I haz the power, 2017-09-12 18:15:31]

Description was changed from

==========
tracing: Add private footprint

Private footprint is a cross-platform, consistent, validated measurement of the
amount of memory a process is using which is:
- private
- non-discardable
- anonymous [not backed by a file]
- Either resident, compressed, or swapped
This plumbs it through Tracing and adds it to the memory metric definitions.

BUG=chromium:737325
==========

to

==========
tracing: Add private footprint

Private footprint is a cross-platform, consistent, validated measurement of the
amount of memory a process is using which is:
- private
- non-discardable
- anonymous [not backed by a file]
- Either resident, compressed, or swapped
This plumbs it through Tracing and adds it to the memory metric definitions.

BUG=chromium:737325

Review-Url: https://chromiumcodereview.appspot.com/3012213002
Committed:
https://chromium.googlesource.com/external/github.com/catapult-project/catapu...
==========

[commit-bot: I haz the power, 2017-09-12 18:15:32]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/github.com/catapult-project/catapu...

[erikchen, 2017-09-12 22:09:01]

erikchen@chromium.org changed reviewers:
+ erikchen@chromium.org

[erikchen, 2017-09-12 22:09:02]

Awesome thanks! lgtm