Add a control benchmark.

Add a control benchmark.

I'm thinking of using this in perf with something like:
   ratio(fill(filter("test=foo")), fill(filter("test=control")))

Does that make sense to you?

Not sure that this is really a good control bench on all bots,
but I propose we just run it a bit and find out if it needs work.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/44d43d8d6e4f9321c9001f269ff433bd06aa81e1

[mtklein_C, 2015-05-06 17:12:28]

mtklein@chromium.org changed reviewers:
+ jcgregorio@google.com

[mtklein, 2015-05-06 17:13:14]

The CQ bit was checked by mtklein@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-05-06 17:13:29]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1129823003/1

[commit-bot: I haz the power, 2015-05-06 17:19:43]

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

[commit-bot: I haz the power, 2015-05-06 17:19:44]

Dry run: This issue passed the CQ dry run.

[jcgregorio, 2015-05-06 19:38:40]

lgtm

[mtklein, 2015-05-06 19:41:36]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-05-06 19:41:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1129823003/1

[commit-bot: I haz the power, 2015-05-06 19:42:10]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/44d43d8d6e4f9321c9001f269ff433bd06aa81e1