Reland of [Android][Telemetry] Add support for multiple power monitors

Reland of [Android][Telemetry] Add support for multiple power monitors (patchset #1 id:1 of https://codereview.chromium.org/1252923003/)

Reason for revert:
This wasn't actually the cause of the failure.

Original issue's description:
> Revert of [Android][Telemetry] Add support for multiple power monitors (patchset #4 id:60001 of https://codereview.chromium.org/1255673002/)
>
> Reason for revert:
> speculative revert: this is the prime suspect for the telemetry_perf_unittests failure on http://build.chromium.org/p/chromium.linux/builders/Android%20Tests%20(dbg)
>
> Original issue's description:
> > [Android][Telemetry] Add support for multiple power monitors
> >
> > BUG=513004
> >
> > Committed: https://crrev.com/a36acb95c375d4de17277cadbe8d56b45a80d5ce
> > Cr-Commit-Position: refs/heads/master@{#340208}
>
> TBR=jdduke@chromium.org,nednguyen@google.com,rnephew@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=513004
>
> Committed: https://crrev.com/d0e348febc608e96bc5ae4ee877f626e2e3fcb38
> Cr-Commit-Position: refs/heads/master@{#340271}

TBR=jdduke@chromium.org,nednguyen@google.com,rnephew@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=513004
Committed: https://crrev.com/25dc860a7012b63dfe1ec1c393e28627454fce4a
Cr-Commit-Position: refs/heads/master@{#340275}

[jbudorick, 2015-07-24 14:21:36]

Created Reland of [Android][Telemetry] Add support for multiple power monitors

[commit-bot: I haz the power, 2015-07-24 14:21:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1252993002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1252993002/1

[commit-bot: I haz the power, 2015-07-24 14:22:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-24 14:23:30]

Patchset 1 (id:??) landed as
https://crrev.com/25dc860a7012b63dfe1ec1c393e28627454fce4a
Cr-Commit-Position: refs/heads/master@{#340275}