Added new histograms for packet size connectivity test.

R=jar@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/79153003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236528 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236528