Move proxies into pc/.

Bug: webrtc:12787
Change-Id: Ia244d9d22d35436a02cf5a448bd1520cb66ff352
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/220321
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34141}
diff --git a/pc/test/integration_test_helpers.h b/pc/test/integration_test_helpers.h
index f015312..117f1b4 100644
--- a/pc/test/integration_test_helpers.h
+++ b/pc/test/integration_test_helpers.h
@@ -37,7 +37,6 @@
 #include "api/media_stream_interface.h"
 #include "api/media_types.h"
 #include "api/peer_connection_interface.h"
-#include "api/peer_connection_proxy.h"
 #include "api/rtc_error.h"
 #include "api/rtc_event_log/rtc_event_log_factory.h"
 #include "api/rtc_event_log/rtc_event_log_factory_interface.h"
@@ -84,6 +83,7 @@
 #include "pc/media_session.h"
 #include "pc/peer_connection.h"
 #include "pc/peer_connection_factory.h"
+#include "pc/peer_connection_proxy.h"
 #include "pc/rtp_media_utils.h"
 #include "pc/session_description.h"
 #include "pc/test/fake_audio_capture_module.h"