Negotiate the same SRTP crypto suites for every DTLS association formed.

webrtc/pc/peerconnection_integrationtest.cc

Index: webrtc/pc/peerconnection_integrationtest.cc
diff --git a/webrtc/pc/peerconnection_integrationtest.cc b/webrtc/pc/peerconnection_integrationtest.cc
index d818300c23f1fe4846d899b3eab589ced74fe771..3c86143f4fb0c429805dd80dcab8b185377b6356 100644
--- a/webrtc/pc/peerconnection_integrationtest.cc
+++ b/webrtc/pc/peerconnection_integrationtest.cc
@@ -2336,6 +2336,34 @@ TEST_F(PeerConnectionIntegrationTest, AddSctpDataChannelInSubsequentOffer) {
                  kDefaultTimeout);
 }
 
+// Set up a connection initially just using SCTP data channels, later upgrading
+// to audio/video, ensuring frames are received end-to-end. Effectively the
+// inverse of the test above.
+// This was broken in M57; see https://crbug.com/711243
+TEST_F(PeerConnectionIntegrationTest, SctpDataChannelToAudioVideoUpgrade) {
+  ASSERT_TRUE(CreatePeerConnectionWrappers());
+  ConnectFakeSignaling();
+  // Do initial offer/answer with just data channel.
+  caller()->CreateDataChannel();
+  caller()->CreateAndSetAndSignalOffer();
+  ASSERT_TRUE_WAIT(SignalingStateStable(), kDefaultTimeout);
+  // Wait until data can be sent over the data channel.
+  ASSERT_TRUE_WAIT(callee()->data_channel() != nullptr, kDefaultTimeout);
+  ASSERT_TRUE_WAIT(caller()->data_observer()->IsOpen(), kDefaultTimeout);
+  ASSERT_TRUE_WAIT(callee()->data_observer()->IsOpen(), kDefaultTimeout);
+
+  // Do subsequent offer/answer with two-way audio and video. Audio and video
+  // should end up bundled on the DTLS/ICE transport already used for data.
+  caller()->AddAudioVideoMediaStream();
+  callee()->AddAudioVideoMediaStream();
+  caller()->CreateAndSetAndSignalOffer();
+  ASSERT_TRUE_WAIT(SignalingStateStable(), kDefaultTimeout);
+  ExpectNewFramesReceivedWithWait(
+      kDefaultExpectedAudioFrameCount, kDefaultExpectedVideoFrameCount,
+      kDefaultExpectedAudioFrameCount, kDefaultExpectedVideoFrameCount,
+      kMaxWaitForFramesMs);
+}
+
 #endif  // HAVE_SCTP
 
 // Test that the ICE connection and gathering states eventually reach