GitLab

This is a preparation to add tests for limiting total number of sockets.

TEST=Covered by net_unittests.

http://crbug.com/15093

Review URL: http://codereview.chromium.org/149159

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@19975 0039d316-1c4b-4281-b951-d872f2087c98