Verify alternative server certificate validity for origin.

net/base/net_error_list.h

Index: net/base/net_error_list.h
diff --git a/net/base/net_error_list.h b/net/base/net_error_list.h
index 6f152c9ce5140161d7fc34bc9141aeae05093957..7a8281f532bff0f0653a0affbaaa79ce7488df5f 100644
--- a/net/base/net_error_list.h
+++ b/net/base/net_error_list.h
@@ -636,6 +636,11 @@ NET_ERROR(PROXY_HTTP_1_1_REQUIRED, -366)
 // The PAC script terminated fatally and must be reloaded.
 NET_ERROR(PAC_SCRIPT_TERMINATED, -367)
 
+// The certificate offered by the alternative server is not valid for the
+// origin, a violation of HTTP Alternative Services specification Section 2.1,
+// https://tools.ietf.org/id/draft-ietf-httpbis-alt-svc-06.html#host_auth.
+NET_ERROR(ALTERNATIVE_CERT_NOT_VALID_FOR_ORIGIN, -368)
+
 // The cache does not have the requested entry.
 NET_ERROR(CACHE_MISS, -400)