Remove the support of fallback from DTLS to SDES.

p2p/base/transportdescriptionfactory.cc

 /*
  *  Copyright 2012 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 101 matching lines @@
   }
 
   // This digest algorithm is used to produce the a=fingerprint lines in SDP.
   // RFC 4572 Section 5 requires that those lines use the same hash function as
   // the certificate's signature, which is what CreateFromCertificate does.
   desc->identity_fingerprint.reset(
       rtc::SSLFingerprint::CreateFromCertificate(certificate_));
   if (!desc->identity_fingerprint) {
     return false;
   }
-  std::string digest_alg;
-  if (!certificate_->ssl_certificate().GetSignatureDigestAlgorithm(
-          &digest_alg)) {
-    LOG(LS_ERROR) << "Failed to retrieve the certificate's digest algorithm";
-    return false;
-  }
-
-  desc->identity_fingerprint.reset(
-      rtc::SSLFingerprint::Create(digest_alg, certificate_->identity()));
-  if (!desc->identity_fingerprint.get()) {
-    LOG(LS_ERROR) << "Failed to create identity fingerprint, alg="
-                  << digest_alg;
-    return false;
-  }
 
   // Assign security role.
   desc->connection_role = role;
   return true;
 }
 
 }  // namespace cricket