GitLab

Since almost everything was converted to Create method, now
it can be moved to private section.

While doing this, CanonicalCookieTest::Constructor had to be
converted to Create method as well.

BUG=57061
TEST=net_unittests --gtest_filter=CanonicalCookieTest.Constructor
TEST=ios_net_unittests
R=mmenke@chromium.org

Review-Url: https://codereview.chromium.org/2159373002
Cr-Commit-Position: refs/heads/master@{#407312}