[Telemetry] Decrease `powermetrics` sampling rate on Mac

[Telemetry] Decrease `powermetrics` sampling rate on Mac

This patch changes the sampling rate of `powermetrics` from 20hz to the default - 5s.  We don't need the extra resolution for our measurements and it seems that increasing the sampling rate draws power in and of itself which affects what's being measured.

BUG=None

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276597

[tonyg, 2014-06-11 17:54:53]

lgtm

[commit-bot: I haz the power, 2014-06-11 17:59:56]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jeremy@chromium.org/322423004/1

[commit-bot: I haz the power, 2014-06-11 21:28:01]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)
  win_chromium_x64_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_x64_rel/...)

[commit-bot: I haz the power, 2014-06-11 21:31:18]

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

[commit-bot: I haz the power, 2014-06-11 21:31:19]

Try jobs failed on following builders:
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)
  win_chromium_x64_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_x64_rel/...)

[tonyg, 2014-06-11 22:47:39]

The CQ bit was checked by tonyg@chromium.org

[commit-bot: I haz the power, 2014-06-11 22:49:39]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jeremy@chromium.org/322423004/1

[commit-bot: I haz the power, 2014-06-11 22:52:19]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)
  win_chromium_x64_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_x64_rel/...)

[commit-bot: I haz the power, 2014-06-11 22:53:58]

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

[commit-bot: I haz the power, 2014-06-11 22:53:59]

Try jobs failed on following builders:
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)

[tonyg, 2014-06-12 04:14:48]

The CQ bit was checked by tonyg@chromium.org

[commit-bot: I haz the power, 2014-06-12 04:17:02]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jeremy@chromium.org/322423004/1

[commit-bot: I haz the power, 2014-06-12 09:17:37]

Change committed as 276597