Remove libsrtp 2.0.0 compatibility code.

webrtc/pc/srtpsession.cc

Index: webrtc/pc/srtpsession.cc
diff --git a/webrtc/pc/srtpsession.cc b/webrtc/pc/srtpsession.cc
index e8b29460a71d6e6eeb7702832c240a34de4a7cff..67ae9a6629fb4163935344d52e401053c9ea3a13 100644
--- a/webrtc/pc/srtpsession.cc
+++ b/webrtc/pc/srtpsession.cc
@@ -154,21 +154,11 @@ bool SrtpSession::GetRtpAuthParams(uint8_t** key, int* key_len, int* tag_len) {
   // stream_template will be the reference context for other streams.
   // Let's use it for getting the keys.
   srtp_stream_ctx_t* srtp_context = session_->stream_template;
-#if defined(SRTP_MAX_MKI_LEN)
-  // libsrtp 2.1.0
   if (srtp_context && srtp_context->session_keys &&
       srtp_context->session_keys->rtp_auth) {
     external_hmac = reinterpret_cast<ExternalHmacContext*>(
         srtp_context->session_keys->rtp_auth->state);
   }
-#else
-  // libsrtp 2.0.0
-  // TODO(jbauch): Remove after switching to libsrtp 2.1.0
-  if (srtp_context && srtp_context->rtp_auth) {
-    external_hmac =
-        reinterpret_cast<ExternalHmacContext*>(srtp_context->rtp_auth->state);
-  }
-#endif
 
   if (!external_hmac) {
     LOG(LS_ERROR) << "Failed to get auth keys from libsrtp!.";