Only set certificate on DTLS transport if fingerprint is found in SDP.

webrtc/api/test/fakertccertificategenerator.h

 /*
  *  Copyright 2013 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 116 matching lines @@
 
   FakeRTCCertificateGenerator() : should_fail_(false) {}
 
   void set_should_fail(bool should_fail) {
     should_fail_ = should_fail;
   }
 
   void use_original_key() { key_index_ = 0; }
   void use_alternate_key() { key_index_ = 1; }
 
+  int generated_certificates() { return generated_certificates_; }
+
   void GenerateCertificateAsync(
       const rtc::KeyParams& key_params,
       const rtc::Optional<uint64_t>& expires_ms,
       const rtc::scoped_refptr<rtc::RTCCertificateGeneratorCallback>&
           callback) override {
     // The certificates are created from constant PEM strings and use its coded
     // expiration time, we do not support modifying it.
     RTC_DCHECK(!expires_ms);
     MessageData* msg = new MessageData(
         rtc::scoped_refptr<rtc::RTCCertificateGeneratorCallback>(callback));
@@ skipping 56 matching lines @@
     rtc::scoped_refptr<rtc::RTCCertificateGeneratorCallback> callback =
         message_data->data();
     rtc::scoped_refptr<rtc::RTCCertificate> certificate;
     switch (msg->message_id) {
       case MSG_SUCCESS_RSA:
       case MSG_SUCCESS_ECDSA: {
         rtc::KeyType key_type =
             msg->message_id == MSG_SUCCESS_RSA ? rtc::KT_RSA : rtc::KT_ECDSA;
         certificate = rtc::RTCCertificate::FromPEM(get_pem(key_type));
         RTC_DCHECK(certificate);
+        ++generated_certificates_;
         callback->OnSuccess(certificate);
         break;
       }
       case MSG_FAILURE:
         callback->OnFailure();
         break;
     }
     delete message_data;
   }
 
   bool should_fail_;
   int key_index_ = 0;
+  int generated_certificates_ = 0;
 };
 
 #endif  // WEBRTC_API_TEST_FAKERTCCERTIFICATEGENERATOR_H_