Add telemetry_unittests and telemetry_perf_unittests.

NOTRY=true
BUG=156398

Review URL: https://codereview.chromium.org/145013014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246939 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246939