[Cleanup] Add missing #include. Remove useless ones. IWYU part 2.

This is a follow-up to
https://webrtc-review.googlesource.com/c/src/+/106280.
This time the whole code base is covered.
Some files may have not been fixed though, whenever the IWYU tool
was breaking the build.

Bug: webrtc:8311
Change-Id: I2c31f552a87e887d33931d46e87b6208b1e483ef
Reviewed-on: https://webrtc-review.googlesource.com/c/111965
Commit-Queue: Yves Gerey <yvesg@google.com>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25830}
diff --git a/pc/statscollector.h b/pc/statscollector.h
index a3c5992..eb810e5 100644
--- a/pc/statscollector.h
+++ b/pc/statscollector.h
@@ -14,6 +14,7 @@
 #ifndef PC_STATSCOLLECTOR_H_
 #define PC_STATSCOLLECTOR_H_
 
+#include <stdint.h>
 #include <map>
 #include <memory>
 #include <string>
@@ -23,7 +24,10 @@
 #include "api/mediastreaminterface.h"
 #include "api/peerconnectioninterface.h"
 #include "api/statstypes.h"
+#include "p2p/base/port.h"
 #include "pc/peerconnectioninternal.h"
+#include "rtc_base/network_constants.h"
+#include "rtc_base/sslcertificate.h"
 
 namespace webrtc {