GN: Tighten up test target visibility + refactorings

webrtc/modules/video_coding/BUILD.gn

Index: webrtc/modules/video_coding/BUILD.gn
diff --git a/webrtc/modules/video_coding/BUILD.gn b/webrtc/modules/video_coding/BUILD.gn
index 9b611bb72f6ded94a411467cf3066225df407321..b9d9566fd33a2b1e69419df7f2ec64c21c85a57f 100644
--- a/webrtc/modules/video_coding/BUILD.gn
+++ b/webrtc/modules/video_coding/BUILD.gn
@@ -378,7 +378,9 @@ if (rtc_include_tests) {
 
   rtc_source_set("video_coding_modules_tests") {
     testonly = true
-
+    if (!is_android && !is_ios) {  # Generated targets makes this check break.
+      visibility = [ "//webrtc/modules:modules_tests" ]
+    }
     sources = [
       "codecs/h264/test/h264_impl_unittest.cc",
       "codecs/test/videoprocessor_integrationtest.cc",
@@ -479,6 +481,9 @@ if (rtc_include_tests) {
 
   rtc_source_set("video_coding_unittests") {
     testonly = true
+    if (!is_android && !is_ios) {  # Generated targets makes this check break.
+      visibility = [ "//webrtc/modules:modules_unittests" ]
+    }
     sources = [
       "codecs/test/packet_manipulator_unittest.cc",
       "codecs/test/stats_unittest.cc",