Refactoring ./webrtc/modules/BUILD.gn for gn check

webrtc/modules/audio_coding/BUILD.gn

Index: webrtc/modules/audio_coding/BUILD.gn
diff --git a/webrtc/modules/audio_coding/BUILD.gn b/webrtc/modules/audio_coding/BUILD.gn
index 70ecc55dc2aa86d3f2739bdd6d91567fe112be17..96cdebaa3ca0f1760935ad515e71bb8edceec8ca 100644
--- a/webrtc/modules/audio_coding/BUILD.gn
+++ b/webrtc/modules/audio_coding/BUILD.gn
@@ -540,7 +540,14 @@ rtc_static_library("isac") {
 }
 
 rtc_static_library("isac_c") {
-  visibility = [ ":*" ]  # Only targets in this file can depend on this.
+  # Only targets in this file should depend on this.
+  # We are adding an exception for the ../:modules_tests target.
+  visibility = [
+    ":*",
+    "//webrtc/modules:modules_tests",
+    "//webrtc/modules:modules_unittests",
+  ]
+
   sources = [
     "codecs/isac/main/include/audio_decoder_isac.h",
     "codecs/isac/main/include/audio_encoder_isac.h",
@@ -808,7 +815,12 @@ rtc_static_library("pcm16b") {
 }
 
 rtc_source_set("pcm16b_c") {
-  visibility = [ ":*" ]  # Only targets in this file can depend on this.
+  # Only targets in this file should depend on this.
+  # We are adding an exception for the ../:modules_tests target.
+  visibility = [
+    ":*",
+    "//webrtc/modules/:modules_tests",
+  ]
   sources = [
     "codecs/pcm16b/pcm16b.c",
     "codecs/pcm16b/pcm16b.h",