diff --git a/webrtc/modules/congestion_controller/congestion_controller.cc b/webrtc/modules/congestion_controller/congestion_controller.cc
index f7e7e5625a..1c90d5cb9e 100644
--- a/webrtc/modules/congestion_controller/congestion_controller.cc
+++ b/webrtc/modules/congestion_controller/congestion_controller.cc
@@ -64,6 +64,11 @@ class WrappingBitrateEstimator : public RemoteBitrateEstimator {
 
   virtual ~WrappingBitrateEstimator() {}
 
+  void IncomingPacketFeedbackVector(
+      const std::vector<PacketInfo>& packet_feedback_vector) override {
+    assert(false);
+  }
+
   void IncomingPacket(int64_t arrival_time_ms,
                       size_t payload_size,
                       const RTPHeader& header) override {
diff --git a/webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h b/webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h
index dfeedfce85..c7f1ffa46d 100644
--- a/webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h
+++ b/webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h
@@ -45,12 +45,10 @@ struct ReceiveBandwidthEstimatorStats {};
 class RemoteBitrateEstimator : public CallStatsObserver, public Module {
  public:
   static const int kDefaultMinBitrateBps = 30000;
-  virtual ~RemoteBitrateEstimator() {}
+  ~RemoteBitrateEstimator() override {}
 
   virtual void IncomingPacketFeedbackVector(
-      const std::vector<PacketInfo>& packet_feedback_vector) {
-    assert(false);
-  }
+      const std::vector<PacketInfo>& packet_feedback_vector) = 0;
 
   // Called for each incoming packet. Updates the incoming payload bitrate
   // estimate and the over-use detector. If an over-use is detected the
diff --git a/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.cc b/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.cc
index 6730cbb611..49d4e3a94a 100644
--- a/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.cc
+++ b/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.cc
@@ -69,6 +69,11 @@ RemoteBitrateEstimatorSingleStream::~RemoteBitrateEstimatorSingleStream() {
   }
 }
 
+void RemoteBitrateEstimatorSingleStream::IncomingPacketFeedbackVector(
+    const std::vector<PacketInfo>& packet_feedback_vector) {
+  assert(false);
+}
+
 void RemoteBitrateEstimatorSingleStream::IncomingPacket(
     int64_t arrival_time_ms,
     size_t payload_size,
diff --git a/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.h b/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.h
index aa238d1e96..013ead4d36 100644
--- a/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.h
+++ b/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.h
@@ -29,6 +29,8 @@ class RemoteBitrateEstimatorSingleStream : public RemoteBitrateEstimator {
                                      Clock* clock);
   virtual ~RemoteBitrateEstimatorSingleStream();
 
+  void IncomingPacketFeedbackVector(
+      const std::vector<PacketInfo>& packet_feedback_vector) override;
   void IncomingPacket(int64_t arrival_time_ms,
                       size_t payload_size,
                       const RTPHeader& header) override;