Fix visibility of api/units build targets.

Bug: None
Change-Id: Ie5f44ba9f5565b1a51175de2f4514829edb3dd03
Reviewed-on: https://webrtc-review.googlesource.com/c/104161
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25032}
diff --git a/api/units/BUILD.gn b/api/units/BUILD.gn
index 7dbddf4..66a85ff 100644
--- a/api/units/BUILD.gn
+++ b/api/units/BUILD.gn
@@ -9,6 +9,7 @@
 import("../../webrtc.gni")
 
 rtc_source_set("data_rate") {
+  visibility = [ "*" ]
   sources = [
     "data_rate.cc",
     "data_rate.h",
@@ -23,6 +24,7 @@
 }
 
 rtc_source_set("data_size") {
+  visibility = [ "*" ]
   sources = [
     "data_size.cc",
     "data_size.h",
@@ -33,7 +35,9 @@
     "../../rtc_base:rtc_base_approved",
   ]
 }
+
 rtc_source_set("time_delta") {
+  visibility = [ "*" ]
   sources = [
     "time_delta.cc",
     "time_delta.h",
@@ -46,6 +50,7 @@
 }
 
 rtc_source_set("timestamp") {
+  visibility = [ "*" ]
   sources = [
     "timestamp.cc",
     "timestamp.h",