diff --git a/call/rtp_stream_receiver_controller.cc b/call/rtp_stream_receiver_controller.cc
index 7150b34bdb..8cefa2dffc 100644
--- a/call/rtp_stream_receiver_controller.cc
+++ b/call/rtp_stream_receiver_controller.cc
@@ -31,9 +31,7 @@ RtpStreamReceiverController::Receiver::Receiver(
 }
 
 RtpStreamReceiverController::Receiver::~Receiver() {
-  // Don't require return value > 0, since for RTX we currently may
-  // have multiple Receiver objects with the same sink.
-  // TODO(nisse): Consider adding a DCHECK when RtxReceiveStream is wired up.
+  // This may fail, if corresponding AddSink in the constructor failed.
   controller_->RemoveSink(sink_);
 }
 
@@ -58,7 +56,7 @@ bool RtpStreamReceiverController::AddSink(uint32_t ssrc,
   return demuxer_.AddSink(ssrc, sink);
 }
 
-size_t RtpStreamReceiverController::RemoveSink(
+bool RtpStreamReceiverController::RemoveSink(
     const RtpPacketSinkInterface* sink) {
   RTC_DCHECK_RUN_ON(&demuxer_sequence_);
   return demuxer_.RemoveSink(sink);
diff --git a/call/rtp_stream_receiver_controller.h b/call/rtp_stream_receiver_controller.h
index 38b2f11d9e..46d04f73f8 100644
--- a/call/rtp_stream_receiver_controller.h
+++ b/call/rtp_stream_receiver_controller.h
@@ -35,10 +35,6 @@ class RtpStreamReceiverController
       uint32_t ssrc,
       RtpPacketSinkInterface* sink) override;
 
-  // Thread-safe wrappers for the corresponding RtpDemuxer methods.
-  bool AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink) override;
-  size_t RemoveSink(const RtpPacketSinkInterface* sink) override;
-
   // TODO(bugs.webrtc.org/7135): Not yet responsible for parsing.
   bool OnRtpPacket(const RtpPacketReceived& packet);
 
@@ -56,6 +52,10 @@ class RtpStreamReceiverController
     RtpPacketSinkInterface* const sink_;
   };
 
+  // Thread-safe wrappers for the corresponding RtpDemuxer methods.
+  bool AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink);
+  bool RemoveSink(const RtpPacketSinkInterface* sink);
+
   // TODO(bugs.webrtc.org/11993): We expect construction and all methods to be
   // called on the same thread/tq. Currently this is the worker thread
   // (including OnRtpPacket) but a more natural fit would be the network thread.
diff --git a/call/rtp_stream_receiver_controller_interface.h b/call/rtp_stream_receiver_controller_interface.h
index 68a9e7daa9..793d0bc145 100644
--- a/call/rtp_stream_receiver_controller_interface.h
+++ b/call/rtp_stream_receiver_controller_interface.h
@@ -36,9 +36,6 @@ class RtpStreamReceiverControllerInterface {
   virtual std::unique_ptr<RtpStreamReceiverInterface> CreateReceiver(
       uint32_t ssrc,
       RtpPacketSinkInterface* sink) = 0;
-  // For registering additional sinks, needed for FlexFEC.
-  virtual bool AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink) = 0;
-  virtual size_t RemoveSink(const RtpPacketSinkInterface* sink) = 0;
 };
 
 }  // namespace webrtc