TransportFeedback must be able to start with dropped packets.

webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback_unittest.cc
index 203d70fab153a8342b043c7b8109324ceae8f028..07f9049c8543d1343873fb038cd2de670aa70d9e 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback_unittest.cc
@@ -359,15 +359,18 @@ TEST(RtcpPacketTest, TransportFeedback_Limits) {
   // Sequence number wrap above 0x8000.
   std::unique_ptr<TransportFeedback> packet(new TransportFeedback());
   packet->WithBase(0, 0);
+  EXPECT_TRUE(packet->WithReceivedPacket(0x0, 0));
   EXPECT_TRUE(packet->WithReceivedPacket(0x8000, 1000));
 
   packet.reset(new TransportFeedback());
   packet->WithBase(0, 0);
+  EXPECT_TRUE(packet->WithReceivedPacket(0x0, 0));
   EXPECT_FALSE(packet->WithReceivedPacket(0x8000 + 1, 1000));
 
   // Packet status count max 0xFFFF.
   packet.reset(new TransportFeedback());
   packet->WithBase(0, 0);
+  EXPECT_TRUE(packet->WithReceivedPacket(0x0, 0));
   EXPECT_TRUE(packet->WithReceivedPacket(0x8000, 1000));
   EXPECT_TRUE(packet->WithReceivedPacket(0xFFFF, 2000));
   EXPECT_FALSE(packet->WithReceivedPacket(0, 3000));