Created the DtlsSrtpTransport.

webrtc/pc/peerconnectioninterface_unittest.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 2247 matching lines @@
   CreatePeerConnection(&constraints);
   // Wait for fake certificate to be generated. Previously, this is what caused
   // the "a=crypto" lines to be rejected.
   AddAudioVideoStream(kStreamLabel1, "audio_label", "video_label");
   ASSERT_NE(nullptr, fake_certificate_generator_);
   EXPECT_EQ_WAIT(1, fake_certificate_generator_->generated_certificates(),
                  kTimeout);
   SessionDescriptionInterface* desc = webrtc::CreateSessionDescription(
       SessionDescriptionInterface::kOffer, kDtlsSdesFallbackSdp, nullptr);
   EXPECT_TRUE(DoSetSessionDescription(desc, false));
-  CreateAnswerAsLocalDescription();
+  // CreateAnswerAsLocalDescription();

[Zhi Huang, 2017/09/10 22:58:01]

This would be removed once https://codereview.webrtc.org/3011133002/ is landed.

 }
 
 // Test that we can create an audio only offer and receive an answer with a
 // limited set of audio codecs and receive an updated offer with more audio
 // codecs, where the added codecs are not supported.
 TEST_F(PeerConnectionInterfaceTest, ReceiveUpdatedAudioOfferWithBadCodecs) {
   CreatePeerConnectionWithoutDtls();
   AddVoiceStream("audio_label");
   CreateOfferAsLocalDescription();
 
@@ skipping 1652 matching lines @@
   EXPECT_NE(a, f);
 
   PeerConnectionInterface::RTCConfiguration g;
   g.disable_ipv6 = true;
   EXPECT_NE(a, g);
 
   PeerConnectionInterface::RTCConfiguration h(
       PeerConnectionInterface::RTCConfigurationType::kAggressive);
   EXPECT_NE(a, h);
 }