Use SequenceChecker from public API

Bug: webrtc:12419
Change-Id: I00cca16a0ec70246156ba00b97aa7ae5ccbf5364
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/205323
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33220}
diff --git a/pc/rtc_stats_collector.cc b/pc/rtc_stats_collector.cc
index 040ee4d..139b33f 100644
--- a/pc/rtc_stats_collector.cc
+++ b/pc/rtc_stats_collector.cc
@@ -11,6 +11,7 @@
 #include "pc/rtc_stats_collector.h"
 
 #include <stdio.h>
+
 #include <algorithm>
 #include <cstdint>
 #include <map>
@@ -25,6 +26,7 @@
 #include "api/rtp_parameters.h"
 #include "api/rtp_receiver_interface.h"
 #include "api/rtp_sender_interface.h"
+#include "api/sequence_checker.h"
 #include "api/stats/rtc_stats.h"
 #include "api/stats/rtcstats_objects.h"
 #include "api/task_queue/queued_task.h"
@@ -55,7 +57,6 @@
 #include "rtc_base/ssl_stream_adapter.h"
 #include "rtc_base/string_encode.h"
 #include "rtc_base/strings/string_builder.h"
-#include "rtc_base/synchronization/sequence_checker.h"
 #include "rtc_base/time_utils.h"
 #include "rtc_base/trace_event.h"