Revert of Add a library for running external commands, providing timeouts and test injection.

Revert of Add a library for running external commands, providing timeouts and test injection. (patchset #2 id:140001 of https://codereview.chromium.org/1302513006/ )

Reason for revert:
CT Perf tasks are immediately failing:
https://uberchromegw.corp.google.com/i/skia-ct-master/run_chromium_perf_on_workers.build101-m5.chrome-bot.log.INFO.20150819-130840.6185

It is likely unrelated to this CL but I am going to try reverting it and rerunning to see what happens.

Original issue's description:
> Reland of Add a library for running external commands, providing timeouts and test injection. (patchset #1 id:1 of https://codereview.chromium.org/1295043002/ )
> 
> Reason for revert:
> Fixed bug in original code - see patchset #2.
> 
> Original issue's description:
> > Revert of Add a library for running external commands, providing timeouts and test injection. (patchset #2 id:40001 of https://codereview.chromium.org/1290913004/ )
> > 
> > Reason for revert:
> > CT Chromium Perf tasks are failing with:
> > 
> > E0815 11:07:22.649344   13091 exec.go:193] Command exited with invalid argument: python /b/skia-repo/go/src/go.skia.org/infra/ct/py/sync_skia_in_chrome.py --destination=/b/storage/chromium_builds/linux_base --fetch_target=chromium --chrome_revision=6ae54795f6d077e31f4fb42540ead46f4141f2bb --skia_revision=fb28cd2b13d76c324570341e1155aaadc1b532b6
> > 
> > Original issue's description:
> > > Add a library for running external commands, providing timeouts and test injection.
> > > 
> > > BUG=skia:4106
> > > 
> > > Committed: https://skia.googlesource.com/buildbot/+/b65fde6749a3e060938cd280c7e281e29516edc1
> > 
> > TBR=jcgregorio@google.com,benjaminwagner@google.com
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=skia:4106
> > 
> > Committed: https://skia.googlesource.com/buildbot/+/ac6c1292955c888d35f6c01cf97d3b6ff4029424
> 
> BUG=skia:4106
> 
> Committed: https://skia.googlesource.com/buildbot/+/a12e89205d4145b4da14b0a7d5b95b15b029ada9

TBR=jcgregorio@google.com,benjaminwagner@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4106
Committed: https://skia.googlesource.com/buildbot/+/0a44649b05aa6f864a45268f681f88328f93796d

[rmistry, 2015-08-19 20:11:34]

Created Revert of Add a library for running external commands, providing
timeouts and test injection.

[commit-bot: I haz the power, 2015-08-19 20:11:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1299493004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1299493004/1

[commit-bot: I haz the power, 2015-08-19 20:11:57]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/buildbot/+/0a44649b05aa6f864a45268f681f88328f93...

[dogben, 2015-08-20 01:59:28]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1300273002/ by benjaminwagner@google.com.

The reason for reverting is: Reland after fix..