[Cleanup] Add missing #include. Remove useless ones.

This CL is the result of running include-what-you-use tool on part
of the code base (audio target and dependencies) plus manual fixes.

bug: webrtc:8311
Change-Id: I277d281ce943c3ecc1bd45fd8d83055931743604
Reviewed-on: https://webrtc-review.googlesource.com/c/106280
Commit-Queue: Yves Gerey <yvesg@google.com>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25311}

modules/rtp_rtcp/source/rtp_header_parser.cc

@@ -9,9 +9,12 @@
  */
 #include "modules/rtp_rtcp/include/rtp_header_parser.h"
 
+#include <string.h>
+
 #include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
 #include "modules/rtp_rtcp/source/rtp_utility.h"
 #include "rtc_base/criticalsection.h"
+#include "rtc_base/thread_annotations.h"
 
 namespace webrtc {