Improve testing of SRTP external auth code paths.

webrtc/pc/externalhmac.h

 /*
  *  Copyright 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 16 matching lines @@
 // the auth_type of srtp_policy_t. The application must first register auth
 // functions and the corresponding authentication id using
 // crypto_kernel_replace_auth_type function.
 
 #include <stdint.h>
 
 #ifdef HAVE_SRTP
 #include "third_party/libsrtp/crypto/include/auth.h"
 #endif  // HAVE_SRTP
 
-#if defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
+#if defined(HAVE_SRTP)
 
 #define EXTERNAL_HMAC_SHA1 SRTP_HMAC_SHA1 + 1
 #define HMAC_KEY_LENGTH 20
 
 // The HMAC context structure used to store authentication keys.
 // The pointer to the key  will be allocated in the external_hmac_init function.
 // This pointer is owned by srtp_t in a template context.
 typedef struct {
   uint8_t key[HMAC_KEY_LENGTH];
   int key_length;
@@ skipping 16 matching lines @@
                                        int msg_octets);
 
 srtp_err_status_t external_hmac_compute(ExternalHmacContext* state,
                                         const void* message,
                                         int msg_octets,
                                         int tag_len,
                                         uint8_t* result);
 
 srtp_err_status_t external_crypto_init();
 
-#endif  // defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
+#endif  // defined(HAVE_SRTP)
 #endif  // WEBRTC_PC_EXTERNALHMAC_H_