Wire up FlexfecSender in RTPSenderVideo.

webrtc/modules/rtp_rtcp/source/flexfec_sender_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/flexfec_sender_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/flexfec_sender_unittest.cc b/webrtc/modules/rtp_rtcp/source/flexfec_sender_unittest.cc
index ca114abeb3d4675b3cb5c8613fe572134b983d0f..3de2b5299cc80a49c07618c12f7090ad4123bbc0 100644
--- a/webrtc/modules/rtp_rtcp/source/flexfec_sender_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/flexfec_sender_unittest.cc
@@ -32,6 +32,7 @@ constexpr uint32_t kFlexfecSsrc = 5678;
 const std::vector<RtpExtension> kNoRtpHeaderExtensions;
 // Assume a single protected media SSRC.
 constexpr size_t kFlexfecMaxHeaderSize = 32;
+constexpr size_t kRtpHeaderExtensionBaseHeaderSize = 4;
 constexpr size_t kPayloadLength = 50;
 
 constexpr int64_t kInitialSimulatedClockTime = 1;
@@ -180,6 +181,7 @@ TEST(FlexfecSenderTest, NoRtpHeaderExtensionsForBweByDefault) {
   SimulatedClock clock(kInitialSimulatedClockTime);
   FlexfecSender sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
                        kRtpHeaderExtensions, &clock);
+  EXPECT_EQ(kRtpHeaderSize, sender.RtpHeaderLength());
   auto fec_packet = GenerateSingleFlexfecPacket(&sender);
 
   EXPECT_FALSE(fec_packet->HasExtension<AbsoluteSendTime>());
@@ -193,6 +195,8 @@ TEST(FlexfecSenderTest, RegisterAbsoluteSendTimeRtpHeaderExtension) {
   SimulatedClock clock(kInitialSimulatedClockTime);
   FlexfecSender sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
                        kRtpHeaderExtensions, &clock);
+  EXPECT_EQ(kRtpHeaderSize + kRtpHeaderExtensionBaseHeaderSize + 4U,
+            sender.RtpHeaderLength());
   auto fec_packet = GenerateSingleFlexfecPacket(&sender);
 
   EXPECT_TRUE(fec_packet->HasExtension<AbsoluteSendTime>());
@@ -206,6 +210,8 @@ TEST(FlexfecSenderTest, RegisterTransmissionOffsetRtpHeaderExtension) {
   SimulatedClock clock(kInitialSimulatedClockTime);
   FlexfecSender sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
                        kRtpHeaderExtensions, &clock);
+  EXPECT_EQ(kRtpHeaderSize + kRtpHeaderExtensionBaseHeaderSize + 4U,
+            sender.RtpHeaderLength());
   auto fec_packet = GenerateSingleFlexfecPacket(&sender);
 
   EXPECT_FALSE(fec_packet->HasExtension<AbsoluteSendTime>());
@@ -219,6 +225,8 @@ TEST(FlexfecSenderTest, RegisterTransportSequenceNumberRtpHeaderExtension) {
   SimulatedClock clock(kInitialSimulatedClockTime);
   FlexfecSender sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
                        kRtpHeaderExtensions, &clock);
+  EXPECT_EQ(kRtpHeaderSize + kRtpHeaderExtensionBaseHeaderSize + 4U,
+            sender.RtpHeaderLength());
   auto fec_packet = GenerateSingleFlexfecPacket(&sender);
 
   EXPECT_FALSE(fec_packet->HasExtension<AbsoluteSendTime>());
@@ -234,6 +242,8 @@ TEST(FlexfecSenderTest, RegisterAllRtpHeaderExtensionsForBwe) {
   SimulatedClock clock(kInitialSimulatedClockTime);
   FlexfecSender sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
                        kRtpHeaderExtensions, &clock);
+  EXPECT_EQ(kRtpHeaderSize + kRtpHeaderExtensionBaseHeaderSize + 3 * 4U,
+            sender.RtpHeaderLength());
   auto fec_packet = GenerateSingleFlexfecPacket(&sender);
 
   EXPECT_TRUE(fec_packet->HasExtension<AbsoluteSendTime>());