Revert of Sync more GN unit tests with GYP.

components/audio_modem/BUILD.gn

Index: components/audio_modem/BUILD.gn
diff --git a/components/audio_modem/BUILD.gn b/components/audio_modem/BUILD.gn
index 154f40f20eda2c0460aebcc36d489d84c9961499..32f396374c712736f806ccb14929573dcaad75a9 100644
--- a/components/audio_modem/BUILD.gn
+++ b/components/audio_modem/BUILD.gn
@@ -2,12 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("audio_modem") {
-  public = [
-    "public/audio_modem_types.h",
-    "public/modem.h",
-    "public/whispernet_client.h",
-  ]
+static_library("audio_modem") {
   sources = [
     "audio_modem_switches.cc",
     "audio_modem_switches.h",
@@ -20,6 +15,9 @@
     "constants.cc",
     "modem_impl.cc",
     "modem_impl.h",
+    "public/audio_modem_types.h",
+    "public/modem.h",
+    "public/whispernet_client.h",
   ]
 
   deps = [
@@ -32,7 +30,6 @@
 }
 
 source_set("test_support") {
-  testonly = true
   sources = [
     "test/random_samples.cc",
     "test/random_samples.h",
@@ -42,25 +39,8 @@
     "test/stub_whispernet_client.h",
   ]
 
-  public_deps = [
-    ":audio_modem",
-  ]
   deps = [
     "//base",
     "//media",
   ]
 }
-
-source_set("unit_tests") {
-  testonly = true
-  sources = [
-    "audio_player_unittest.cc",
-    "audio_recorder_unittest.cc",
-    "modem_unittest.cc",
-  ]
-
-  deps = [
-    ":test_support",
-    "//testing/gtest",
-  ]
-}