Reland "Let WebRtcVideoChannel::ResetUnsignaledRecvStream delete all default streams."

This is a reland of d335426.

The revert was premature: the failing tests were known to be flaky
(crbug.com/1066515, crbug.com/1066453, crbug.com/1066407, crbug.com/1066399)

Original change's description:
> Let WebRtcVideoChannel::ResetUnsignaledRecvStream delete all default streams.
>
> This CL changes WebRtcVideoChannel::ResetUnsignaledRecvStream so
> that it deletes all default streams created by
> WebRtcVideoChannel::AddRecvStream. This is needed for the case that
> there are lingering default streams, whose SSRCs are different
> from the SSRCs that were subsequently signaled. This can happen
> when there are multiple "m= sections" and the early media is
> sent to an "m= section" that is later not supposed to be the
> sink for that particular SSRC.
>
> Default streams whose SSRC match the subsequently signaled
> SSRC is already handled here: https://source.chromium.org/chromium/chromium/src/+/master:third_party/webrtc/media/engine/webrtc_video_engine.cc;l=1386;drc=22387b44ff173d263b434889d394cea90368ab06?originalUrl=https:%2F%2Fcs.chromium.org%2F
>
> Bug: webrtc:11477
> Change-Id: I96ed7e35b4904fb0757fe5824f8afa6f1b9a565e
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/172622
> Reviewed-by: Harald Alvestrand <[email protected]>
> Reviewed-by: Magnus Flodman <[email protected]>
> Commit-Queue: Rasmus Brandt <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#30971}

[email protected],[email protected]

Bug: webrtc:11477
Change-Id: I70b8fa47b4d1d0aa36fed4d8612e13fa7f992925
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/172782
Reviewed-by: Rasmus Brandt <[email protected]>
Commit-Queue: Rasmus Brandt <[email protected]>
Cr-Commit-Position: refs/heads/master@{#30986}

Author: rasmusbrandt

media/engine/webrtc_video_engine.cc

@@ -1482,6 +1482,21 @@ void WebRtcVideoChannel::ResetUnsignaledRecvStream() {
   RTC_DCHECK_RUN_ON(&thread_checker_);
   RTC_LOG(LS_INFO) << "ResetUnsignaledRecvStream.";
   unsignaled_stream_params_ = StreamParams();
+
+  // Delete any created default streams.
+  auto it = receive_streams_.begin();
+  while (it != receive_streams_.end()) {
+    auto delete_it = receive_streams_.end();
+    if (it->second->IsDefaultStream()) {
+      delete_it = it;
+    }
+    ++it;
+    if (delete_it != receive_streams_.end()) {
+      DeleteReceiveStream(delete_it->second);
+      // |it| is not invalidated by this erase.
+      receive_streams_.erase(delete_it->first);
+    }
+  }
 }
 
 bool WebRtcVideoChannel::SetSink(

media/engine/webrtc_video_engine_unittest.cc

@@ -5836,7 +5836,6 @@ TEST_F(WebRtcVideoChannelTest, RecvUnsignaledSsrcWithSignaledStreamId) {
   // Reset the unsignaled stream to clear the cache. This time when
   // a default video receive stream is created it won't have a sync_group.
   channel_->ResetUnsignaledRecvStream();
-  ASSERT_TRUE(channel_->RemoveRecvStream(kIncomingUnsignalledSsrc));
   EXPECT_EQ(0u, fake_call_->GetVideoReceiveStreams().size());
 
   channel_->OnPacketReceived(packet, /* packet_time_us */ -1);
@@ -5845,6 +5844,37 @@ TEST_F(WebRtcVideoChannelTest, RecvUnsignaledSsrcWithSignaledStreamId) {
       fake_call_->GetVideoReceiveStreams()[0]->GetConfig().sync_group.empty());
 }
 
+TEST_F(WebRtcVideoChannelTest,
+       ResetUnsignaledRecvStreamDeletesAllDefaultStreams) {
+  // No receive streams to start with.
+  EXPECT_TRUE(fake_call_->GetVideoReceiveStreams().empty());
+
+  // Packet with unsignaled SSRC is received.
+  const size_t kDataLength = 12;
+  uint8_t data[kDataLength];
+  memset(data, 0, sizeof(data));
+  rtc::SetBE32(&data[8], kIncomingUnsignalledSsrc);
+  rtc::CopyOnWriteBuffer packet(data, kDataLength);
+  channel_->OnPacketReceived(packet, /* packet_time_us */ -1);
+
+  // Default receive stream created.
+  const auto& receivers1 = fake_call_->GetVideoReceiveStreams();
+  ASSERT_EQ(receivers1.size(), 1u);
+  EXPECT_EQ(receivers1[0]->GetConfig().rtp.remote_ssrc,
+            kIncomingUnsignalledSsrc);
+
+  // Stream with another SSRC gets signaled.
+  channel_->ResetUnsignaledRecvStream();
+  constexpr uint32_t kIncomingSignalledSsrc = kIncomingUnsignalledSsrc + 1;
+  ASSERT_TRUE(channel_->AddRecvStream(
+      cricket::StreamParams::CreateLegacy(kIncomingSignalledSsrc)));
+
+  // New receiver is for the signaled stream.
+  const auto& receivers2 = fake_call_->GetVideoReceiveStreams();
+  ASSERT_EQ(receivers2.size(), 1u);
+  EXPECT_EQ(receivers2[0]->GetConfig().rtp.remote_ssrc, kIncomingSignalledSsrc);
+}
+
 // Test BaseMinimumPlayoutDelayMs on receive streams.
 TEST_F(WebRtcVideoChannelTest, BaseMinimumPlayoutDelayMs) {
   // Test that set won't work for non-existing receive streams.