Enable TLS channeld id by default.

net/socket/ssl_client_socket_nss.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_SOCKET_SSL_CLIENT_SOCKET_NSS_H_
 #define NET_SOCKET_SSL_CLIENT_SOCKET_NSS_H_
 
 #include <certt.h>
 #include <keyt.h>
 #include <nspr.h>
@@ skipping 144 matching lines @@
   scoped_refptr<Core> core_;
 
   CompletionCallback user_connect_callback_;
 
   CertVerifyResult server_cert_verify_result_;
   HashValueVector side_pinned_public_keys_;
 
   CertVerifier* const cert_verifier_;
   scoped_ptr<SingleRequestCertVerifier> verifier_;
 
-  // For domain bound certificates in client auth.
+  // The service for retrieving Channel ID keys.  May be NULL.
   ServerBoundCertService* server_bound_cert_service_;
 
   // ssl_session_cache_shard_ is an opaque string that partitions the SSL
   // session cache. i.e. sessions created with one value will not attempt to
   // resume on the socket with a different value.
   const std::string ssl_session_cache_shard_;
 
   // True if the SSL handshake has been completed.
   bool completed_handshake_;
 
@@ skipping 15 matching lines @@
   // Added the following code Debugging in release mode.
   mutable base::Lock lock_;
   // This is mutable so that CalledOnValidThread can set it.
   // It's guarded by |lock_|.
   mutable base::PlatformThreadId valid_thread_id_;
 };
 
 }  // namespace net
 
 #endif  // NET_SOCKET_SSL_CLIENT_SOCKET_NSS_H_