Avoid toggling default receive streams in WebRtcVideoChannel2.

webrtc/media/engine/webrtcvideoengine2_unittest.cc

 /*
  *  Copyright (c) 2004 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 3951 matching lines @@
   recv_stream = fake_call_->GetVideoReceiveStreams()[0];
   EXPECT_EQ(rtpHeader.ssrc, recv_stream->GetConfig().rtp.remote_ssrc);
   // Verify that the receive stream sinks to a renderer.
   webrtc::VideoFrame video_frame3(CreateBlackFrameBuffer(4, 4), 300, 0,
                                   webrtc::kVideoRotation_0);
   recv_stream->InjectFrame(video_frame3);
   EXPECT_EQ(3, renderer.num_rendered_frames());
 #endif
 }
 
+// This test verifies that when a new default stream is created for a new
+// unsignaled SSRC, the new stream does not overwrite any old stream that had
+// been the default receive stream before being properly signaled.
+TEST_F(WebRtcVideoChannel2Test,
+       NewUnsignaledStreamDoesNotDestroyPreviouslyUnsignaledStream) {
+  cricket::VideoRecvParameters parameters;
+  parameters.codecs.push_back(GetEngineCodec("VP8"));
+  ASSERT_TRUE(channel_->SetRecvParameters(parameters));
+
+  // No streams signaled and no packets received, so we should not have any
+  // stream objects created yet.
+  EXPECT_EQ(0u, fake_call_->GetVideoReceiveStreams().size());
+
+  // Receive packet on an unsignaled SSRC.
+  uint8_t data[kMinRtpPacketLen];
+  cricket::RtpHeader rtp_header;
+  rtp_header.payload_type = GetEngineCodec("VP8").id;
+  rtp_header.seq_num = rtp_header.timestamp = 0;
+  rtp_header.ssrc = kSsrcs3[0];
+  cricket::SetRtpHeader(data, sizeof(data), rtp_header);
+  rtc::CopyOnWriteBuffer packet(data, sizeof(data));
+  rtc::PacketTime packet_time;
+  channel_->OnPacketReceived(&packet, packet_time);
+  // Default receive stream should be created.
+  ASSERT_EQ(1u, fake_call_->GetVideoReceiveStreams().size());
+  FakeVideoReceiveStream* recv_stream0 =
+      fake_call_->GetVideoReceiveStreams()[0];
+  EXPECT_EQ(kSsrcs3[0], recv_stream0->GetConfig().rtp.remote_ssrc);
+
+  // Signal the SSRC.
+  EXPECT_TRUE(
+      channel_->AddRecvStream(cricket::StreamParams::CreateLegacy(kSsrcs3[0])));
+  ASSERT_EQ(1u, fake_call_->GetVideoReceiveStreams().size());
+  recv_stream0 = fake_call_->GetVideoReceiveStreams()[0];
+  EXPECT_EQ(kSsrcs3[0], recv_stream0->GetConfig().rtp.remote_ssrc);
+
+  // Receive packet on a different unsignaled SSRC.
+  rtp_header.ssrc = kSsrcs3[1];
+  cricket::SetRtpHeader(data, sizeof(data), rtp_header);
+  packet.SetData(data, sizeof(data));
+  channel_->OnPacketReceived(&packet, packet_time);
+  // New default receive stream should be created, but old stream should remain.
+  ASSERT_EQ(2u, fake_call_->GetVideoReceiveStreams().size());
+  EXPECT_EQ(recv_stream0, fake_call_->GetVideoReceiveStreams()[0]);
+  FakeVideoReceiveStream* recv_stream1 =
+      fake_call_->GetVideoReceiveStreams()[1];
+  EXPECT_EQ(kSsrcs3[1], recv_stream1->GetConfig().rtp.remote_ssrc);
+}
+
 TEST_F(WebRtcVideoChannel2Test, CanSentMaxBitrateForExistingStream) {
   AddSendStream();
 
   cricket::FakeVideoCapturer capturer;
   EXPECT_TRUE(channel_->SetVideoSend(last_ssrc_, true, nullptr, &capturer));
   cricket::VideoFormat capture_format_hd =
       capturer.GetSupportedFormats()->front();
   EXPECT_EQ(1280, capture_format_hd.width);
   EXPECT_EQ(720, capture_format_hd.height);
   EXPECT_EQ(cricket::CS_RUNNING, capturer.Start(capture_format_hd));
@@ skipping 546 matching lines @@
 
 TEST_F(WebRtcVideoChannel2SimulcastTest,
        NoSimulcastScreenshareWithoutConference) {
   webrtc::test::ScopedFieldTrials override_field_trials_(
       "WebRTC-SimulcastScreenshare/Enabled/");
   VerifySimulcastSettings(cricket::VideoCodec("VP8"), 1280, 720, 3, 1, true,
                           false);
 }
 
 }  // namespace cricket