diff --git a/media/engine/webrtcvideoengine.h b/media/engine/webrtcvideoengine.h
index 62096bceb4..f75be26227 100644
--- a/media/engine/webrtcvideoengine.h
+++ b/media/engine/webrtcvideoengine.h
@@ -51,19 +51,7 @@ class Thread;
 namespace cricket {
 
 class DecoderFactoryAdapter;
-class VideoCapturer;
-class VideoProcessor;
-class VideoRenderer;
-class VoiceMediaChannel;
-class WebRtcDecoderObserver;
-class WebRtcEncoderObserver;
-class WebRtcLocalStreamInfo;
-class WebRtcRenderAdapter;
 class WebRtcVideoChannel;
-class WebRtcVideoChannelRecvInfo;
-class WebRtcVideoChannelSendInfo;
-class WebRtcVoiceEngine;
-class WebRtcVoiceMediaChannel;
 
 class UnsignalledSsrcHandler {
  public:
diff --git a/modules/pacing/paced_sender.h b/modules/pacing/paced_sender.h
index 888bedfb5d..5ac9ccf98a 100644
--- a/modules/pacing/paced_sender.h
+++ b/modules/pacing/paced_sender.h
@@ -24,7 +24,6 @@ namespace webrtc {
 class AlrDetector;
 class BitrateProber;
 class Clock;
-class ProbeClusterCreatedObserver;
 class RtcEventLog;
 class IntervalBudget;
 
diff --git a/modules/video_coding/include/video_coding.h b/modules/video_coding/include/video_coding.h
index 880d5f556d..5aeb222592 100644
--- a/modules/video_coding/include/video_coding.h
+++ b/modules/video_coding/include/video_coding.h
@@ -32,13 +32,7 @@ namespace webrtc {
 
 class Clock;
 class EncodedImageCallback;
-// TODO(pbos): Remove VCMQMSettingsCallback completely. This might be done by
-// removing the VCM and use VideoSender/VideoReceiver as a public interface
-// directly.
-class VCMQMSettingsCallback;
-class VideoBitrateAllocator;
 class VideoEncoder;
-class VideoDecoder;
 struct CodecSpecificInfo;
 
 class EventFactory {
diff --git a/rtc_base/nethelpers.h b/rtc_base/nethelpers.h
index e118b27dbc..3901df85f2 100644
--- a/rtc_base/nethelpers.h
+++ b/rtc_base/nethelpers.h
@@ -27,8 +27,6 @@
 
 namespace rtc {
 
-class AsyncResolverTest;
-
 // AsyncResolver will perform async DNS resolution, signaling the result on
 // the SignalDone from AsyncResolverInterface when the operation completes.
 class AsyncResolver : public SignalThread, public AsyncResolverInterface {
diff --git a/video/receive_statistics_proxy.h b/video/receive_statistics_proxy.h
index 2fa4e084e8..73768a4609 100644
--- a/video/receive_statistics_proxy.h
+++ b/video/receive_statistics_proxy.h
@@ -35,8 +35,6 @@
 namespace webrtc {
 
 class Clock;
-class ViECodec;
-class ViEDecoderObserver;
 struct CodecSpecificInfo;
 
 class ReceiveStatisticsProxy : public VCMReceiveStatisticsCallback,
diff --git a/video/video_send_stream.h b/video/video_send_stream.h
index b65129e6cf..bbf706aeb4 100644
--- a/video/video_send_stream.h
+++ b/video/video_send_stream.h
@@ -105,7 +105,6 @@ class VideoSendStream : public webrtc::VideoSendStream {
   friend class test::VideoSendStreamPeer;
 
   class ConstructionTask;
-  class DestructAndGetRtpStateTask;
 
   rtc::Optional<float> GetPacingFactorOverride() const;
 
diff --git a/video/video_stream_decoder.h b/video/video_stream_decoder.h
index c542d8badb..c7d04b7b14 100644
--- a/video/video_stream_decoder.h
+++ b/video/video_stream_decoder.h
@@ -26,11 +26,7 @@
 
 namespace webrtc {
 
-class CallStatsObserver;
-class ChannelStatsObserver;
-class EncodedImageCallback;
 class ReceiveStatisticsProxy;
-class VideoRenderCallback;
 
 namespace vcm {
 class VideoReceiver;
@@ -44,8 +40,6 @@ enum StreamType {
 class VideoStreamDecoder : public VCMReceiveCallback,
                            public VCMReceiveStatisticsCallback {
  public:
-  friend class ChannelStatsObserver;
-
   VideoStreamDecoder(
       vcm::VideoReceiver* video_receiver,
       VCMFrameTypeCallback* vcm_frame_type_callback,