Update WebRTC to build against libsrtp 2.0

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.
  */
 
 #ifndef WEBRTC_PC_EXTERNALHMAC_H_
 #define WEBRTC_PC_EXTERNALHMAC_H_
 
 // External libsrtp HMAC auth module which implements methods defined in
 // auth_type_t.
 // The default auth module will be replaced only when the ENABLE_EXTERNAL_AUTH
 // flag is enabled. This allows us to access to authentication keys,
 // as the default auth implementation doesn't provide access and avoids
 // hashing each packet twice.
 
 // How will libsrtp select this module?
 // Libsrtp defines authentication function types identified by an unsigned
 // integer, e.g. HMAC_SHA1 is 3. Using authentication ids, the application
 // can plug any desired authentication modules into libsrtp.
 // libsrtp also provides a mechanism to select different auth functions for
 // individual streams. This can be done by setting the right value in
 // 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.
-#if defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
 
 #include "webrtc/base/basictypes.h"
+#ifdef HAVE_SRTP
 extern "C" {
 #ifdef SRTP_RELATIVE_PATH
 #include "auth.h"  // NOLINT
 #else
-#include "third_party/libsrtp/srtp/crypto/include/auth.h"
+#include "third_party/libsrtp/crypto/include/auth.h"
 #endif  // SRTP_RELATIVE_PATH
 }
+#endif  // HAVE_SRTP
+
+#if defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
 
 #define EXTERNAL_HMAC_SHA1 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 @@
 err_status_t external_hmac_compute(ExternalHmacContext* state,
                                    const void* message,
                                    int msg_octets,
                                    int tag_len,
                                    uint8_t* result);
 
 err_status_t external_crypto_init();
 
 #endif  // defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
 #endif  // WEBRTC_PC_EXTERNALHMAC_H_