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/peer_connection_factory.h b/pc/peer_connection_factory.h
index 80d2592..cbc7397 100644
--- a/pc/peer_connection_factory.h
+++ b/pc/peer_connection_factory.h
@@ -14,6 +14,7 @@
 
 #include <stdint.h>
 #include <stdio.h>
+
 #include <memory>
 #include <string>
 
@@ -30,6 +31,7 @@
 #include "api/rtc_event_log/rtc_event_log_factory_interface.h"
 #include "api/rtp_parameters.h"
 #include "api/scoped_refptr.h"
+#include "api/sequence_checker.h"
 #include "api/task_queue/task_queue_factory.h"
 #include "api/transport/network_control.h"
 #include "api/transport/sctp_transport_factory_interface.h"
@@ -41,7 +43,6 @@
 #include "pc/connection_context.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/rtc_certificate_generator.h"
-#include "rtc_base/synchronization/sequence_checker.h"
 #include "rtc_base/thread.h"
 #include "rtc_base/thread_annotations.h"