Add profiling, integrate into Butler/Annotee.

Add profiling, integrate into Butler/Annotee.

Add a profiling package to run a profiling HTTP server and allow
periodic profiling metric collection.

Integrate this into LogDog's Annotee and Butler programs.

BUG=chromium:671616
TEST=local
  - Ran Butler locally, bound to HTTP server, seems to work.

Committed: https://github.com/luci/luci-go/commit/f5e96b94465d190bb8022c900506e17e7c5e1a70

[dnj, 2016-12-06 20:25:19]

dnj@chromium.org changed reviewers:
+ martiniss@chromium.org

[dnj, 2016-12-06 20:25:20]

PTAL

Sorry this took so long, got caught up in profiling :)

[martiniss, 2016-12-06 20:36:43]

lgtm, but I don't see any instructions on use of this anywhere.. :(

[dnj, 2016-12-06 20:43:09]

The CQ bit was checked by dnj@chromium.org

[commit-bot: I haz the power, 2016-12-06 20:43:13]

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, 2016-12-06 20:49:48]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1481056989451220, "parent_rev":
"01914a3866dfb095a96f0b43abad4ecc956d3168", "commit_rev":
"f5e96b94465d190bb8022c900506e17e7c5e1a70"}

[commit-bot: I haz the power, 2016-12-06 20:49:51]

Description was changed from

==========
Add profiling, integrate into Butler/Annotee.

Add a profiling package to run a profiling HTTP server and allow
periodic profiling metric collection.

Integrate this into LogDog's Annotee and Butler programs.

BUG=chromium:671616
TEST=local
  - Ran Butler locally, bound to HTTP server, seems to work.
==========

to

==========
Add profiling, integrate into Butler/Annotee.

Add a profiling package to run a profiling HTTP server and allow
periodic profiling metric collection.

Integrate this into LogDog's Annotee and Butler programs.

BUG=chromium:671616
TEST=local
  - Ran Butler locally, bound to HTTP server, seems to work.

Committed:
https://github.com/luci/luci-go/commit/f5e96b94465d190bb8022c900506e17e7c5e1a70
==========

[commit-bot: I haz the power, 2016-12-06 20:49:53]

Committed patchset #1 (id:1) as
https://github.com/luci/luci-go/commit/f5e96b94465d190bb8022c900506e17e7c5e1a70