diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index 3b094f99de..75feb793b2 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -16,14 +16,16 @@
 #include <algorithm>
 #include <memory>
 #include <set>
+#include <string>
+#include <type_traits>
 #include <utility>
 
 #include "absl/algorithm/container.h"
 #include "absl/strings/match.h"
+#include "absl/strings/string_view.h"
 #include "api/jsep_ice_candidate.h"
 #include "api/rtp_parameters.h"
 #include "api/rtp_transceiver_direction.h"
-#include "api/task_queue/queued_task.h"
 #include "api/transport/webrtc_key_value_config.h"
 #include "api/uma_metrics.h"
 #include "api/video/video_codec_constants.h"
@@ -31,6 +33,7 @@
 #include "call/packet_receiver.h"
 #include "media/base/media_channel.h"
 #include "media/base/media_config.h"
+#include "media/base/media_engine.h"
 #include "media/base/rid_description.h"
 #include "media/base/stream_params.h"
 #include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
@@ -44,7 +47,9 @@
 #include "pc/channel.h"
 #include "pc/ice_server_parsing.h"
 #include "pc/rtp_receiver.h"
+#include "pc/rtp_receiver_proxy.h"
 #include "pc/rtp_sender.h"
+#include "pc/rtp_sender_proxy.h"
 #include "pc/sctp_transport.h"
 #include "pc/simulcast_description.h"
 #include "pc/webrtc_session_description_factory.h"
@@ -53,6 +58,7 @@
 #include "rtc_base/location.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/net_helper.h"
+#include "rtc_base/network.h"
 #include "rtc_base/network_constants.h"
 #include "rtc_base/ref_counted_object.h"
 #include "rtc_base/socket_address.h"
diff --git a/pc/peer_connection.h b/pc/peer_connection.h
index 3555ffbfe9..3f3dda601e 100644
--- a/pc/peer_connection.h
+++ b/pc/peer_connection.h
@@ -14,6 +14,7 @@
 #include <stdint.h>
 
 #include <functional>
+#include <iosfwd>
 #include <map>
 #include <memory>
 #include <set>
diff --git a/tools_webrtc/iwyu/apply-iwyu b/tools_webrtc/iwyu/apply-iwyu
index c0242aa6b4..68b71fb24e 100755
--- a/tools_webrtc/iwyu/apply-iwyu
+++ b/tools_webrtc/iwyu/apply-iwyu
@@ -14,8 +14,14 @@
 #
 # To get iwyu on Debian/glinux, do "sudo apt-get install iwyu".
 
+# Set this to 1 to get more debug information.
+# Set this to 2 to also get a dump of the iwyu tool output.
+DEBUG=1
+
 set -e
-set -x
+if [ $DEBUG -gt 0 ]; then
+  set -x
+fi
 
 IWYU_TOOL="${IWYU_TOOL:-/usr/bin/iwyu_tool}"
 FIX_INCLUDE="${FIX_INCLUDE:-/usr/bin/fix_include}"
@@ -57,13 +63,17 @@ if [ ! -f $FILE ]; then
   fi
   FILE_CC=$FILE.cc
 else
-  # Exact file, no .h file
+  # Exact cc file, no .h file - but iwyu will modify .h anyway if it exists.
   FILE_CC=$FILE
-  FILE_H=""
+  if [ -f $(dirname $FILE)/$(basename -s .cc $FILE).h ]; then
+    FILE_H=$(dirname $FILE)/$(basename -s .cc $FILE).h
+  else
+    FILE_H=""
+  fi
 fi
 
 # IWYU has a confusing set of exit codes. Discard it.
-"$IWYU_TOOL" -p "$COMPILE_COMMANDS" "$FILE_CC" \
+"$IWYU_TOOL" -p "$COMPILE_COMMANDS" "$FILE_CC" -- -Xiwyu --no_fwd_decls \
   >& /tmp/includefixes$$ || echo "IWYU done, code $?"
 
 if grep 'fatal error' /tmp/includefixes$$; then
@@ -72,6 +82,9 @@ if grep 'fatal error' /tmp/includefixes$$; then
   rm /tmp/includefixes$$
   exit 1
 else
+  if [ $DEBUG -gt 1 ]; then
+    cat /tmp/includefixes$$
+  fi
   # In compile_commands.json, the file name is recorded
   # as a relative path to the build directory.
   pushd "$(dirname "$COMPILE_COMMANDS")" || error "pushd failed"
diff --git a/tools_webrtc/iwyu/iwyu-filter-list b/tools_webrtc/iwyu/iwyu-filter-list
index 0c0c69558b..2332cd3d61 100644
--- a/tools_webrtc/iwyu/iwyu-filter-list
+++ b/tools_webrtc/iwyu/iwyu-filter-list
@@ -4,3 +4,5 @@
 #include <sys/socket.h>
 #include <ext/alloc_traits.h>
 #include <netinet/in.h>
+#include <__memory/unique_ptr.h>
+#include <__tree>