[SyncFS] Add a UMA to measure RTT in registration

Add a UMA to measure RTT in registering "origin" path.


BUG=None
TEST=Manually
R=asvitkine@chromium.org, tzik@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=269527

[peria, 2014-05-08 06:24:14]

Tsuiki-san,
PTL?

[tzik, 2014-05-08 06:39:09]

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
File chrome/browser/sync_file_system/drive_backend/sync_engine.cc (right):

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
chrome/browser/sync_file_system/drive_backend/sync_engine.cc:536: base::Time
start_time,
const ref?

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
chrome/browser/sync_file_system/drive_backend/sync_engine.cc:539:
base::TimeDelta delta(base::Time::Now() - start_time);
s/Time/TimeTicks/?

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
File chrome/browser/sync_file_system/drive_backend/sync_engine.h (right):

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
chrome/browser/sync_file_system/drive_backend/sync_engine.h:168: SyncStatusCode
status);
Can this function move to anonymous namespace in .cc?

[tzik, 2014-05-08 06:51:06]

https://codereview.chromium.org/269343008/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/269343008/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:27873: +    Round trip time to register
the root path of tracking files in the Sync
Can this be like below for someone who isn't familiar to SyncFS?
"Time elapsed to register an app to SyncFilesystem.  Recorded for each
registration request by apps."

[peria, 2014-05-08 06:51:52]

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
File chrome/browser/sync_file_system/drive_backend/sync_engine.cc (right):

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
chrome/browser/sync_file_system/drive_backend/sync_engine.cc:536: base::Time
start_time,
On 2014/05/08 06:39:10, tzik wrote:
> const ref?

Done.

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
chrome/browser/sync_file_system/drive_backend/sync_engine.cc:539:
base::TimeDelta delta(base::Time::Now() - start_time);
On 2014/05/08 06:39:10, tzik wrote:
> s/Time/TimeTicks/?

Done.

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
File chrome/browser/sync_file_system/drive_backend/sync_engine.h (right):

https://codereview.chromium.org/269343008/diff/1/chrome/browser/sync_file_sys...
chrome/browser/sync_file_system/drive_backend/sync_engine.h:168: SyncStatusCode
status);
On 2014/05/08 06:39:10, tzik wrote:
> Can this function move to anonymous namespace in .cc?

Done.

[peria, 2014-05-08 06:56:13]

https://codereview.chromium.org/269343008/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/269343008/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:27873: +    Round trip time to register
the root path of tracking files in the Sync
On 2014/05/08 06:51:06, tzik wrote:
> Can this be like below for someone who isn't familiar to SyncFS?
> "Time elapsed to register an app to SyncFilesystem.  Recorded for each
> registration request by apps."

Done.

[tzik, 2014-05-08 07:01:46]

Thanks! LGTM.
Please request one of tools/metrics/OWNERS to review.

[peria, 2014-05-08 07:08:04]

jar@
Could you take a look as an owner of tools/metrics?

[peria, 2014-05-09 05:33:00]

On 2014/05/08 07:08:04, peria wrote:
> jar@
> Could you take a look as an owner of tools/metrics?

ping

[peria, 2014-05-09 06:19:39]

Alexei
Would you take a look?

[Alexei Svitkine (slow), 2014-05-09 13:14:48]

lgtm

[peria, 2014-05-09 13:32:47]

The CQ bit was checked by peria@chromium.org

[peria, 2014-05-09 13:34:02]

On 2014/05/09 13:14:48, Alexei Svitkine wrote:
> lgtm

Thank you!
submitting.

[commit-bot: I haz the power, 2014-05-09 13:37:18]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/peria@chromium.org/269343008/30001

[tzik, 2014-05-10 04:47:39]

Committed patchset #3 manually as r269527.