Initialize remoting.ClientSession.PerfStats with zeros

* Initialize remoting.ClientSession.PerfStats with zeros so that caller doesn't need to check the undefined case.
* Add check to StatsAccumulator.Add so that initial zeros will not dilute the result.

BUG=613317
Committed: https://crrev.com/bab89783f15ddb0fedb0a8f5ff03e3e696b2f2af
Cr-Commit-Position: refs/heads/master@{#395408}

[Yuwei, 2016-05-23 17:32:21]

Description was changed from

==========
Initialize remoting.ClientSession.PerfStats with zeros

so that the content matches its type, i.e. @type {number}.

BUG=613317
==========

to

==========
* Initialize remoting.ClientSession.PerfStats with zeros so that caller doesn't
need to check the undefined case.
* Add check to StatsAccumulator.Add so that initial zeros will not dilute the
result. 

BUG=613317
==========

[Yuwei, 2016-05-23 17:39:49]

yuweih@chromium.org changed reviewers:
+ jamiewalch@chromium.org

[Yuwei, 2016-05-23 17:39:50]

Looks like I misunderstood the logging process. Raw stats will be accumulated in
SessionAccumulator and SessionLogger will only send out the stats if the
accumulated stats have any non-zero field. In this case it is safe to initialize
PerfStats with 0's.

Alternatively we can mark all PerfStats' fields with type {number|undefined} to
force its callers to check the undefined case.

PTAL.

[Yuwei, 2016-05-23 17:40:43]

The CQ bit was checked by yuweih@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-05-23 17:41:00]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2004673002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2004673002/20001

[Jamie, 2016-05-23 17:55:41]

Please take a look at the "== undefined" checks in connection_stats.js, since I
don't think they are needed any more with this change.

https://codereview.chromium.org/2004673002/diff/20001/remoting/webapp/base/js...
File remoting/webapp/base/js/stats_accumulator.js (right):

https://codereview.chromium.org/2004673002/diff/20001/remoting/webapp/base/js...
remoting/webapp/base/js/stats_accumulator.js:42: *                   otherwise.
Nit: continuation lines are usually indented 4 spaces relative to the previous
line.

[Yuwei, 2016-05-23 18:14:00]

Removed the unused undefined check and fixed style nit.

Looks like in JSCompiler you can mark a field as non-nullable by adding
exclamation mark at the front.

PTAL :)

https://codereview.chromium.org/2004673002/diff/20001/remoting/webapp/base/js...
File remoting/webapp/base/js/stats_accumulator.js (right):

https://codereview.chromium.org/2004673002/diff/20001/remoting/webapp/base/js...
remoting/webapp/base/js/stats_accumulator.js:42: *                   otherwise.
On 2016/05/23 17:55:41, Jamie wrote:
> Nit: continuation lines are usually indented 4 spaces relative to the previous
> line.

Done.

[Yuwei, 2016-05-23 18:14:21]

The CQ bit was checked by yuweih@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-05-23 18:14:52]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2004673002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2004673002/40001

[Yuwei, 2016-05-23 18:16:40]

https://codereview.chromium.org/2004673002/diff/40001/remoting/webapp/base/js...
File remoting/webapp/base/js/stats_accumulator.js (right):

https://codereview.chromium.org/2004673002/diff/40001/remoting/webapp/base/js...
remoting/webapp/base/js/stats_accumulator.js:40: * @param {Object<number>} stats
Oops... That should be Object<!number> or PerfStats to be more specific. Not
sure why JSCompiler doesn't complain...

[Jamie, 2016-05-23 18:18:27]

LGTM once the !s are removed.

https://codereview.chromium.org/2004673002/diff/40001/remoting/webapp/base/js...
File remoting/webapp/base/js/client_session.js (right):

https://codereview.chromium.org/2004673002/diff/40001/remoting/webapp/base/js...
remoting/webapp/base/js/client_session.js:205: /** @type {!number} */
Number is not a nullable type, so you don't need this (undefined and null are
separate types in JS).

[Yuwei, 2016-05-23 18:25:03]

The CQ bit was checked by yuweih@chromium.org to run a CQ dry run

[Yuwei, 2016-05-23 18:25:23]

https://codereview.chromium.org/2004673002/diff/40001/remoting/webapp/base/js...
File remoting/webapp/base/js/client_session.js (right):

https://codereview.chromium.org/2004673002/diff/40001/remoting/webapp/base/js...
remoting/webapp/base/js/client_session.js:205: /** @type {!number} */
On 2016/05/23 18:18:27, Jamie wrote:
> Number is not a nullable type, so you don't need this (undefined and null are
> separate types in JS).

Done.

[commit-bot: I haz the power, 2016-05-23 18:25:30]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2004673002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2004673002/60001

[commit-bot: I haz the power, 2016-05-23 19:27:48]

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

[commit-bot: I haz the power, 2016-05-23 19:27:50]

Dry run: This issue passed the CQ dry run.

[Yuwei, 2016-05-23 20:40:38]

The CQ bit was checked by yuweih@chromium.org

[Yuwei, 2016-05-23 20:40:39]

The patchset sent to the CQ was uploaded after l-g-t-m from
jamiewalch@chromium.org
Link to the patchset: https://codereview.chromium.org/2004673002/#ps60001
(title: "Reviewer's Feedback")

[commit-bot: I haz the power, 2016-05-23 20:41:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2004673002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2004673002/60001

[commit-bot: I haz the power, 2016-05-23 20:49:57]

Description was changed from

==========
* Initialize remoting.ClientSession.PerfStats with zeros so that caller doesn't
need to check the undefined case.
* Add check to StatsAccumulator.Add so that initial zeros will not dilute the
result. 

BUG=613317
==========

to

==========
* Initialize remoting.ClientSession.PerfStats with zeros so that caller doesn't
need to check the undefined case.
* Add check to StatsAccumulator.Add so that initial zeros will not dilute the
result. 

BUG=613317
==========

[commit-bot: I haz the power, 2016-05-23 20:49:58]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-05-23 20:51:43]

Description was changed from

==========
* Initialize remoting.ClientSession.PerfStats with zeros so that caller doesn't
need to check the undefined case.
* Add check to StatsAccumulator.Add so that initial zeros will not dilute the
result. 

BUG=613317
==========

to

==========
* Initialize remoting.ClientSession.PerfStats with zeros so that caller doesn't
need to check the undefined case.
* Add check to StatsAccumulator.Add so that initial zeros will not dilute the
result.

BUG=613317

Committed: https://crrev.com/bab89783f15ddb0fedb0a8f5ff03e3e696b2f2af
Cr-Commit-Position: refs/heads/master@{#395408}
==========

[commit-bot: I haz the power, 2016-05-23 20:51:44]

Patchset 4 (id:??) landed as
https://crrev.com/bab89783f15ddb0fedb0a8f5ff03e3e696b2f2af
Cr-Commit-Position: refs/heads/master@{#395408}