Revert 246733 "[telemetry] Initial power monitoring integration ..."

Test fails on win:
http://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%282%29/builds/27602/steps/telemetry_unittests/logs/testParsePowerMetricsOutput

MacPlatformBackendTest.testParsePowerMetricsOutput: 
Traceback (most recent call last):
File "E:\b\build\slave\Win7_Tests__2_\build\src\tools\telemetry\telemetry\core\platform\mac_platform_backend_unittest.py", line 42, in testParsePowerMetricsOutput
if not backend.CanMonitorPowerAsync():
File "E:\b\build\slave\Win7_Tests__2_\build\src\tools\telemetry\telemetry\core\platform\mac_platform_backend.py", line 171, in CanMonitorPowerAsync
os_version = int(os.uname()[2].split('.')[0])
AttributeError: 'module' object has no attribute 'uname'

> [telemetry] Initial power monitoring integration on OS X
> 
> Execute powermetrics command line tool and extract initial stats.
> 
> BUG=336555
> NOTRY=true
> 
> Review URL: https://codereview.chromium.org/144493002

TBR=jeremy@chromium.org

Review URL: https://codereview.chromium.org/146233003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246779 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246779