Add samplingTime mode to nanobench

Add samplingTime mode to nanobench

Adds a nanobench mode that takes samples for a fixed amount of time,
rather than taking a fixed amount of samples.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/e1b8958877a512bf83cbc2c72bb31e7d71b06f43

[Chris Dalton, 2015-06-25 03:38:13]

cdalton@nvidia.com changed reviewers:
+ bsalomon@google.com, mtklein@google.com

[mtklein, 2015-06-25 12:06:46]

Seems like a good idea to me.

https://codereview.chromium.org/1204153002/diff/20001/bench/nanobench.cpp
File bench/nanobench.cpp (right):

https://codereview.chromium.org/1204153002/diff/20001/bench/nanobench.cpp#new...
bench/nanobench.cpp:1056: double endTime = GetTimeMs() + samplingTimeMs;
Can we just do this as

timer.start()
do {
  ...
} while (timer.end() < samplingTimeMs);

?

[Chris Dalton, 2015-06-25 19:45:18]

https://codereview.chromium.org/1204153002/diff/20001/bench/nanobench.cpp
File bench/nanobench.cpp (right):

https://codereview.chromium.org/1204153002/diff/20001/bench/nanobench.cpp#new...
bench/nanobench.cpp:1056: double endTime = GetTimeMs() + samplingTimeMs;
On 2015/06/25 12:06:46, mtklein wrote:
> Can we just do this as
> 
> timer.start()
> do {
>   ...
> } while (timer.end() < samplingTimeMs);
> 
> ?

Oh, that's nice. It's not like a real stopwatch that quits counting once you hit
stop :^)

[mtklein, 2015-06-25 19:53:52]

The CQ bit was checked by mtklein@google.com

[mtklein, 2015-06-25 19:53:53]

lgtm

https://codereview.chromium.org/1204153002/diff/40001/bench/nanobench.cpp
File bench/nanobench.cpp (right):

https://codereview.chromium.org/1204153002/diff/40001/bench/nanobench.cpp#new...
bench/nanobench.cpp:1064: timer.end();
Yeah, .end() is probably a bit of a misnomer.  This whole WallTimer API is
really pretty lousy...

[commit-bot: I haz the power, 2015-06-25 19:54:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1204153002/40001

[commit-bot: I haz the power, 2015-06-25 19:54:12]

The author cdalton@nvidia.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[commit-bot: I haz the power, 2015-06-25 19:55:18]

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

[commit-bot: I haz the power, 2015-06-25 19:55:19]

Try jobs failed on following builders:
  skia_presubmit-Trybot on client.skia.fyi (JOB_FAILED,
http://build.chromium.org/p/client.skia.fyi/builders/skia_presubmit-Trybot/bu...)

[Chris Dalton, 2015-06-25 21:00:08]

The CQ bit was checked by cdalton@nvidia.com

[Chris Dalton, 2015-06-25 21:00:09]

The patchset sent to the CQ was uploaded after l-g-t-m from mtklein@google.com
Link to the patchset: https://codereview.chromium.org/1204153002/#ps60001
(title: "Fix windows")

[commit-bot: I haz the power, 2015-06-25 21:00:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1204153002/60001

[commit-bot: I haz the power, 2015-06-25 21:00:30]

The author cdalton@nvidia.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[commit-bot: I haz the power, 2015-06-25 21:01:30]

The author cdalton@nvidia.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[commit-bot: I haz the power, 2015-06-25 21:01:31]

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

[commit-bot: I haz the power, 2015-06-25 21:01:32]

Try jobs failed on following builders:
  skia_presubmit-Trybot on client.skia.fyi (JOB_FAILED,
http://build.chromium.org/p/client.skia.fyi/builders/skia_presubmit-Trybot/bu...)

[Chris Dalton, 2015-06-25 21:03:04]

>> "tools/Stats.h is missing a correct copyright header."

Should I just add one?

[Chris Dalton, 2015-06-25 21:05:18]

Added copyright to tools/Stats.h

[Chris Dalton, 2015-06-26 02:10:48]

The CQ bit was checked by cdalton@nvidia.com

[Chris Dalton, 2015-06-26 02:10:49]

The patchset sent to the CQ was uploaded after l-g-t-m from mtklein@google.com
Link to the patchset: https://codereview.chromium.org/1204153002/#ps80001
(title: "copyright")

[commit-bot: I haz the power, 2015-06-26 02:11:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1204153002/80001

[commit-bot: I haz the power, 2015-06-26 02:11:01]

The author cdalton@nvidia.com has not signed Google Contributor License
Agreement. Please visit https://cla.developers.google.com to sign and manage
CLA.

[commit-bot: I haz the power, 2015-06-26 02:17:13]

Committed patchset #5 (id:80001) as
https://skia.googlesource.com/skia/+/e1b8958877a512bf83cbc2c72bb31e7d71b06f43