diff --git a/media/base/turn_utils.h b/media/base/turn_utils.h
index ed8e282ba7..82e492c028 100644
--- a/media/base/turn_utils.h
+++ b/media/base/turn_utils.h
@@ -18,8 +18,6 @@
 
 namespace cricket {
 
-struct PacketOptions;
-
 // Finds data location within a TURN Channel Message or TURN Send Indication
 // message.
 bool RTC_EXPORT UnwrapTurnPacket(const uint8_t* packet,
diff --git a/media/engine/webrtc_video_engine.h b/media/engine/webrtc_video_engine.h
index c5c06998fa..e8125e12a0 100644
--- a/media/engine/webrtc_video_engine.h
+++ b/media/engine/webrtc_video_engine.h
@@ -40,7 +40,6 @@
 namespace webrtc {
 class VideoDecoderFactory;
 class VideoEncoderFactory;
-struct MediaConfig;
 }  // namespace webrtc
 
 namespace cricket {
diff --git a/media/engine/webrtc_voice_engine.h b/media/engine/webrtc_voice_engine.h
index 6eeb498888..147688b0e0 100644
--- a/media/engine/webrtc_voice_engine.h
+++ b/media/engine/webrtc_voice_engine.h
@@ -38,8 +38,6 @@ class AudioFrameProcessor;
 
 namespace cricket {
 
-class AudioDeviceModule;
-class AudioMixer;
 class AudioSource;
 class WebRtcVoiceMediaChannel;