Update SSL error handling code to account for Subject CN deprecation

components/ssl_errors/error_classification.h

Index: components/ssl_errors/error_classification.h
diff --git a/components/ssl_errors/error_classification.h b/components/ssl_errors/error_classification.h
index b8c472df6697f0607b8cd6b37185ed63fd3c3d9a..efe07c39ab72e85cb62fc28d5cc6e8e58971b6f4 100644
--- a/components/ssl_errors/error_classification.h
+++ b/components/ssl_errors/error_classification.h
@@ -110,14 +110,20 @@ bool IsCertLikelyFromMultiTenantHosting(const GURL& request_url,
 bool IsCertLikelyFromSameDomain(const GURL& request_url,
                                 const net::X509Certificate& cert);
 
-// Returns true if the site's hostname differs from one of the DNS
-// names in the certificate (CN or SANs) only by the presence or
-// absence of the single-label prefix "www". E.g.: (The first domain
-// is hostname and the second domain is a DNS name in the certificate)
+// Returns true if the site's hostname differs from one of the DNS names in the
+// certificate (SANs) only by the presence or absence of the single-label prefix
+// "www". E.g.: (The first domain is the url's hostname and the second domain is
+// a DNS name in the certificate):
 //     www.example.com ~ example.com -> true
 //     example.com ~ www.example.com -> true
 //     www.food.example.com ~ example.com -> false
 //     mail.example.com ~ example.com -> false
+bool IsWWWSubDomainMatch(const GURL& request_url,
+                         const net::X509Certificate& cert);
+
+// Returns true if the site's hostname differs from one of the DNS names in
+// |dns_names| only by the presence or absence of the single-label prefix "www".
+// The matching name from the certificate is returned in |www_match_host_name|.
 bool GetWWWSubDomainMatch(const GURL& request_url,
                           const std::vector<std::string>& dns_names,
                           std::string* www_match_host_name);