telemetry: Increase smoothness threashold to 19ms.

R=nduca@chromium.org
NOTRY=True
BUG=

Review URL: https://codereview.chromium.org/105813002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238983 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238983