Update IWYU tool with a mapping file

Also apply IWYU to all .cc files in pc/, and correct BUILD file to match.
Note: Some files came out wrong when iwyu was applied. These are not included.

Bug: none
Change-Id: Ib5ea46b8fcc505414d0447cca7218ad3afc2e321
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/252280
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36064}
diff --git a/pc/video_track_source_proxy.h b/pc/video_track_source_proxy.h
index 1f6d976..8500a98 100644
--- a/pc/video_track_source_proxy.h
+++ b/pc/video_track_source_proxy.h
@@ -11,7 +11,13 @@
 #ifndef PC_VIDEO_TRACK_SOURCE_PROXY_H_
 #define PC_VIDEO_TRACK_SOURCE_PROXY_H_
 
+#include "absl/types/optional.h"
 #include "api/media_stream_interface.h"
+#include "api/video/recordable_encoded_frame.h"
+#include "api/video/video_frame.h"
+#include "api/video/video_sink_interface.h"
+#include "api/video/video_source_interface.h"
+#include "api/video_track_source_constraints.h"
 #include "pc/proxy.h"
 
 namespace webrtc {
@@ -21,6 +27,7 @@
 // TODO(deadbeef): Move this to .cc file. What threads methods are called on is
 // an implementation detail.
 BEGIN_PROXY_MAP(VideoTrackSource)
+
 PROXY_PRIMARY_THREAD_DESTRUCTOR()
 PROXY_CONSTMETHOD0(SourceState, state)
 BYPASS_PROXY_CONSTMETHOD0(bool, remote)