Revert of Delete Rtx-related methods from RTPPayloadRegistry.

webrtc/modules/rtp_rtcp/test/testAPI/test_api.cc

Index: webrtc/modules/rtp_rtcp/test/testAPI/test_api.cc
diff --git a/webrtc/modules/rtp_rtcp/test/testAPI/test_api.cc b/webrtc/modules/rtp_rtcp/test/testAPI/test_api.cc
index 28be2225b280c64ee9cf1a258b712f830b69e449..b39c8d72dae16fee1e8477083bfaaa25a401bced 100644
--- a/webrtc/modules/rtp_rtcp/test/testAPI/test_api.cc
+++ b/webrtc/modules/rtp_rtcp/test/testAPI/test_api.cc
@@ -162,4 +162,23 @@
   EXPECT_EQ(kRtxRetransmitted, module_->RtxSendStatus());
 }
 
+TEST_F(RtpRtcpAPITest, RtxReceiver) {
+  const uint32_t kRtxSsrc = 1;
+  const int kRtxPayloadType = 119;
+  const int kPayloadType = 100;
+  EXPECT_FALSE(rtp_payload_registry_->RtxEnabled());
+  rtp_payload_registry_->SetRtxSsrc(kRtxSsrc);
+  rtp_payload_registry_->SetRtxPayloadType(kRtxPayloadType, kPayloadType);
+  EXPECT_TRUE(rtp_payload_registry_->RtxEnabled());
+  RTPHeader rtx_header;
+  rtx_header.ssrc = kRtxSsrc;
+  rtx_header.payloadType = kRtxPayloadType;
+  EXPECT_TRUE(rtp_payload_registry_->IsRtx(rtx_header));
+  rtx_header.ssrc = 0;
+  EXPECT_FALSE(rtp_payload_registry_->IsRtx(rtx_header));
+  rtx_header.ssrc = kRtxSsrc;
+  rtx_header.payloadType = 0;
+  EXPECT_TRUE(rtp_payload_registry_->IsRtx(rtx_header));
+}
+
 }  // namespace webrtc