Revert "Avoid sending empty receiver reports with RtcpTransceiver"

This reverts commit e5f1a39.

Reason for revert: Speculative revert due to failing downstream unittest.

Original change's description:
> Avoid sending empty receiver reports with RtcpTransceiver
>
> Bug: None
> Change-Id: Ia017c2df285febefb72ba88ba43366455bde5a78
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/222402
> Reviewed-by: Per Kjellander <[email protected]>
> Commit-Queue: Danil Chapovalov <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#34281}

[email protected],[email protected],[email protected]

Change-Id: I895317ad0381756e97e501a36d6440f83a68b6f8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: None
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/222440
Reviewed-by: Björn Terelius <[email protected]>
Commit-Queue: Björn Terelius <[email protected]>
Cr-Commit-Position: refs/heads/master@{#34284}

modules/rtp_rtcp/source/rtcp_transceiver_impl.cc

@@ -355,12 +355,9 @@ void RtcpTransceiverImpl::CreateCompoundPacket(PacketSender* sender) {
   rtcp::ReceiverReport receiver_report;
   receiver_report.SetSenderSsrc(sender_ssrc);
   receiver_report.SetReportBlocks(CreateReportBlocks(now));
-  if (config_.rtcp_mode == RtcpMode::kCompound ||
-      !receiver_report.report_blocks().empty()) {
-    sender->AppendPacket(receiver_report);
-  }
+  sender->AppendPacket(receiver_report);
 
-  if (!config_.cname.empty() && !sender->IsEmpty()) {
+  if (!config_.cname.empty()) {
     rtcp::Sdes sdes;
     bool added = sdes.AddCName(config_.feedback_ssrc, config_.cname);
     RTC_DCHECK(added) << "Failed to add cname " << config_.cname

modules/rtp_rtcp/source/rtcp_transceiver_impl_unittest.cc

@@ -38,7 +38,6 @@ namespace {
 
 using ::testing::_;
 using ::testing::ElementsAre;
-using ::testing::NiceMock;
 using ::testing::Return;
 using ::testing::SizeIs;
 using ::testing::StrictMock;
@@ -393,47 +392,6 @@ TEST(RtcpTransceiverImplTest, SendsMinimalCompoundPacket) {
   EXPECT_EQ(rtcp_parser.sdes()->chunks()[0].cname, config.cname);
 }
 
-TEST(RtcpTransceiverImplTest, AvoidsEmptyPacketsInReducedMode) {
-  MockTransport transport;
-  EXPECT_CALL(transport, SendRtcp).Times(0);
-  NiceMock<MockReceiveStatisticsProvider> receive_statistics;
-  SimulatedClock clock(0);
-
-  RtcpTransceiverConfig config = DefaultTestConfig();
-  config.clock = &clock;
-  config.outgoing_transport = &transport;
-  config.rtcp_mode = webrtc::RtcpMode::kReducedSize;
-  config.schedule_periodic_compound_packets = false;
-  config.receive_statistics = &receive_statistics;
-  RtcpTransceiverImpl rtcp_transceiver(config);
-
-  rtcp_transceiver.SendCompoundPacket();
-}
-
-TEST(RtcpTransceiverImplTest, AvoidsEmptyReceiverReportsInReducedMode) {
-  RtcpPacketParser rtcp_parser;
-  RtcpParserTransport transport(&rtcp_parser);
-  NiceMock<MockReceiveStatisticsProvider> receive_statistics;
-  SimulatedClock clock(0);
-
-  RtcpTransceiverConfig config = DefaultTestConfig();
-  config.clock = &clock;
-  config.outgoing_transport = &transport;
-  config.rtcp_mode = webrtc::RtcpMode::kReducedSize;
-  config.schedule_periodic_compound_packets = false;
-  config.receive_statistics = &receive_statistics;
-  // Set it to produce something (RRTR) in the "periodic" rtcp packets.
-  config.non_sender_rtt_measurement = true;
-  RtcpTransceiverImpl rtcp_transceiver(config);
-
-  // Rather than waiting for the right time to produce the periodic packet,
-  // trigger it manually.
-  rtcp_transceiver.SendCompoundPacket();
-
-  EXPECT_EQ(rtcp_parser.receiver_report()->num_packets(), 0);
-  EXPECT_GT(rtcp_parser.xr()->num_packets(), 0);
-}
-
 TEST(RtcpTransceiverImplTest, SendsNoRembInitially) {
   const uint32_t kSenderSsrc = 12345;
   SimulatedClock clock(0);