Make some new rtc_base targets publicly visible

Bug: webrtc:9987
Change-Id: I207514c8790d2f3a043ed083790261b1c4b7ba33
Reviewed-on: https://webrtc-review.googlesource.com/c/122084
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26627}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index c52baf1..4462381 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -699,6 +699,7 @@
 }
 
 rtc_source_set("async_resolver_interface") {
+  visibility = [ "*" ]
   # TODO(bugs.webrtc.org/9987): This build target will soon contain
   #                             the following files:
   # sources = [
@@ -708,6 +709,7 @@
 }
 
 rtc_source_set("ip_address") {
+  visibility = [ "*" ]
   # TODO(bugs.webrtc.org/9987): This build target will soon contain
   #                             the following files:
   # sources = [
@@ -717,6 +719,7 @@
 }
 
 rtc_source_set("socket_address") {
+  visibility = [ "*" ]
   # TODO(bugs.webrtc.org/9987): This build target will soon contain
   #                             the following files:
   # sources = [
@@ -743,6 +746,7 @@
 }
 
 rtc_source_set("threading") {
+  visibility = [ "*" ]
   # TODO(bugs.webrtc.org/9987): This build target will soon contain
   #                             the following files:
   # sources = [