net: only False Start with forward secret servers.

net/third_party/nss/ssl/ssl3ext.c

 /*
  * SSL3 Protocol
  *
  * ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
@@ skipping 551 matching lines @@
 ssl3_ServerHandleNextProtoNegoXtn(sslSocket * ss, PRUint16 ex_type, SECItem *data)
 {
     if (ss->firstHsDone || data->len != 0) {
         /* Clients MUST send an empty NPN extension, if any. */
         PORT_SetError(SSL_ERROR_NEXT_PROTOCOL_DATA_INVALID);
         return SECFailure;
     }
 
     ss->xtnData.negotiated[ss->xtnData.numNegotiated++] = ex_type;
 
+    /* TODO: server side NPN support would require calling
+     * ssl3_RegisterServerHelloExtensionSender here in order to echo the
+     * extension back to the client. */
+
     return SECSuccess;
 }
 
 /* ssl3_ValidateNextProtoNego checks that the given block of data is valid: none
  * of the lengths may be 0 and the sum of the lengths must equal the length of
  * the block. */
 SECStatus
 ssl3_ValidateNextProtoNego(const unsigned char* data, unsigned int length)
 {
     unsigned int offset = 0;
@@ skipping 1283 matching lines @@
 
     /* The echoed extension must be empty. */
     if (data->len != 0)
         return SECFailure;
 
     /* Keep track of negotiated extensions. */
     ss->xtnData.negotiated[ss->xtnData.numNegotiated++] = ex_type;
 
     return SECSuccess;
 }