server/discovery: add discovery service

server/discovery: add discovery service

The discovery service accepts a list of service name and uses the
descriptions in the registry. It exposes one method Describe that
returns a list of service names and a file descriptor set that describes
the services, their message and transitive dependencies.

It is not prpc-specific

R=iannucci@chromium.org, dnj@chromium.org, vadimsh@chromium.org, estaab@chromium.org
BUG=

Committed: https://github.com/luci/luci-go/commit/2a51ac93b38b1be1ae9ee2e102940d14610149f4

[nodir, 2016-01-13 00:14:24]

PTAL

[iannucci, 2016-01-13 21:17:03]

lgtm

[nodir, 2016-01-15 23:52:29]

The CQ bit was checked by nodir@chromium.org

[nodir, 2016-01-15 23:52:29]

The patchset sent to the CQ was uploaded after l-g-t-m from
iannucci@chromium.org
Link to the patchset: https://codereview.chromium.org/1571393006/#ps20001
(title: "rebased")

[commit-bot: I haz the power, 2016-01-15 23:52:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1571393006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1571393006/20001

[commit-bot: I haz the power, 2016-01-15 23:54:22]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-01-15 23:54:22]

Try jobs failed on following builders:
  Luci-go Presubmit on master.tryserver.infra (JOB_FAILED,
https://build.chromium.org/p/tryserver.infra/builders/Luci-go%20Presubmit/bui...)

[nodir, 2016-01-16 00:53:04]

The CQ bit was checked by nodir@chromium.org

[commit-bot: I haz the power, 2016-01-16 00:53:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1571393006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1571393006/20001

[commit-bot: I haz the power, 2016-01-16 00:55:12]

Description was changed from

==========
server/discovery: add discovery service

The discovery service accepts a list of service name and uses the
descriptions in the registry. It exposes one method Describe that
returns a list of service names and a file descriptor set that describes
the services, their message and transitive dependencies.

It is not prpc-specific

R=iannucci@chromium.org, dnj@chromium.org, vadimsh@chromium.org,
estaab@chromium.org
BUG=
==========

to

==========
server/discovery: add discovery service

The discovery service accepts a list of service name and uses the
descriptions in the registry. It exposes one method Describe that
returns a list of service names and a file descriptor set that describes
the services, their message and transitive dependencies.

It is not prpc-specific

R=iannucci@chromium.org, dnj@chromium.org, vadimsh@chromium.org,
estaab@chromium.org
BUG=

Committed:
https://github.com/luci/luci-go/commit/2a51ac93b38b1be1ae9ee2e102940d14610149f4
==========

[commit-bot: I haz the power, 2016-01-16 00:55:13]

Committed patchset #2 (id:20001) as
https://github.com/luci/luci-go/commit/2a51ac93b38b1be1ae9ee2e102940d14610149f4