[Telemetry] Small fixes to power monitoring

* Fix FD leak when reading output file.
* Update OS X version check.

BUG=None

Review URL: https://codereview.chromium.org/163183003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251059 0039d316-1c4b-4281-b951-d872f2087c98
Android: add pliard@ to base/android/OWNERS.

NOTRY=True

Review URL: https://codereview.chromium.org/163873002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251060 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251060