Change SSL_PeerCertificateChain to return a CERTCertList.

R=agl@chromium.org,rsleevi@chromium.org
BUG=none
TEST=none

Review URL: https://codereview.chromium.org/25107004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226126 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226126