Reland: WKWebView: Added cert verification API to web controller.
This code is just a skeleton for verification and verification method
is not used for making security decisions or presenting security UI.
The decision to use CertVerifier instead of iOS cert verification API
has not been made yet. But using CertVerifier is easier for
-[WKWebView certificateChain] verification, so this CL uses
CertVerifier.
Original URL: https://codereview.chromium.org/
1230033005/
BUG=462427,462425
Review URL: https://codereview.chromium.org/
1316063008
Cr-Commit-Position: refs/heads/master@{#348699}