Add a DevTools warning for a missing subjectAltName

components/security_state_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <grit-part>
   <!-- Strings describing Chrome security policy for DevTools security panel -->
   <message name="IDS_PRIVATE_USER_DATA_INPUT" desc="Summary phrase for a security problem where the site collects private user data on an insecure page." translateable="false">
     Private User Data Input
   </message>
   <message name="IDS_SAFEBROWSING_WARNING" desc="Summary phrase for a security problem where the site is deemed unsafe by the SafeBrowsing service." translateable="false">
     This page is dangerous (flagged by Google Safe Browsing).
   </message>
   <message name="IDS_SHA1" desc="Summary phrase for a security problem where the site's certificate chain contains a SHA1 signature." translateable="false">
     SHA-1 Certificate
   </message>
   <message name="IDS_SHA1_DESCRIPTION" desc="Description of a security problem where the site's certificate chain contains a SHA1 signature." translateable="false">
     The certificate chain for this site contains a certificate signed using SHA-1.
   </message>
+  <message name="IDS_SUBJECT_ALT_NAME_MISSING" desc="Summary phrase for a security problem where the site's certificate is missing a subjectAltName extension." translateable="false">
+    Subject Alternative Name Missing
+  </message>
+  <message name="IDS_SUBJECT_ALT_NAME_MISSING_DESCRIPTION" desc="Description of a security problem where the site's certificate is missing a subjectAltName extension." translateable="false">
+    The certificate for this site does not contain a Subject Alternative Name extension.
+  </message>
   <message name="IDS_CERTIFICATE_CHAIN_ERROR" desc="Summary phrase for a security problem with the site's certificate." translateable="false">
     Certificate Error
   </message>
   <message name="IDS_CERTIFICATE_CHAIN_ERROR_DESCRIPTION_FORMAT" desc="Description of a security problem with the site's certificate." translateable="false">
     There are issues with the site's certificate chain (<ph name="CERT_ERROR_DESCRIPTION">$1<ex>net::ERR_CERT_AUTHORITY_INVALID</ex></ph>).
   </message>
   <message name="IDS_VALID_SERVER_CERTIFICATE" desc="Summary phrase for a site that has a valid server certificate." translateable="false">
     Valid Certificate
   </message>
   <message name="IDS_VALID_SERVER_CERTIFICATE_DESCRIPTION" desc="Description of a site that has a valid server certificate." translateable="false">
@@ skipping 29 matching lines @@
   <message name="IDS_SSL_AN_OBSOLETE_CIPHER" desc="A phrase to describe an SSL/TLS cipher (e.g. AES_256_CBC) that is old and insecure." translateable="false">
     an obsolete cipher
   </message>
   <message name="IDS_SSL_A_STRONG_CIPHER" desc="A phrase to describe an SSL/TLS cipher (e.g. AES_128_GCM or ChaCha20 with Poly1305) that is modern and secure." translateable="false">
     a strong cipher
   </message>
   <message name="IDS_SSL_KEY_EXCHANGE_WITH_GROUP" desc="A phrase to describe an SSL/TLS ECDHE-based key exchange with a group." translateable="false">
     <ph name="A_KEY_EXCHANGE">$1<ex>ECDHE_RSA</ex></ph> with <ph name="A_GROUP">$2<ex>X25519</ex></ph>
   </message>
 </grit-part>