Remove flags include from p2p/base/datagram_dtls_adaptor.cc.

Bug: webrtc:10616
Change-Id: Icfee86e5648af4eaef2d4a4d8b1caab745b25f41
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/143173
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28376}
diff --git a/p2p/base/datagram_dtls_adaptor.cc b/p2p/base/datagram_dtls_adaptor.cc
index a6e7d30..add07a1 100644
--- a/p2p/base/datagram_dtls_adaptor.cc
+++ b/p2p/base/datagram_dtls_adaptor.cc
@@ -25,7 +25,6 @@
 #include "rtc_base/buffer.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/dscp.h"
-#include "rtc_base/flags.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/message_queue.h"
 #include "rtc_base/rtc_certificate.h"