Revert of Removing unused audio device tests

webrtc/modules/audio_device/BUILD.gn

Index: webrtc/modules/audio_device/BUILD.gn
diff --git a/webrtc/modules/audio_device/BUILD.gn b/webrtc/modules/audio_device/BUILD.gn
index d7fa9353291493c405db0ae8c8328d95f1b4a56a..ddf74c6e9a842a31308437058b61bd279b739eb3 100644
--- a/webrtc/modules/audio_device/BUILD.gn
+++ b/webrtc/modules/audio_device/BUILD.gn
@@ -317,6 +317,29 @@
     ]
     all_dependent_configs = [ ":mock_audio_device_config" ]
   }
+
+  if (!is_ios) {
+    # These tests do not work on ios, see
+    # https://bugs.chromium.org/p/webrtc/issues/detail?id=4755
+    rtc_executable("audio_device_tests") {
+      testonly = true
+      sources = [
+        "test/audio_device_test_api.cc",
+        "test/audio_device_test_defines.h",
+      ]
+      deps = [
+        ":audio_device",
+        "../..:webrtc_common",
+        "../../system_wrappers",
+        "../../test:test_main",
+        "../../test:test_support",
+        "../rtp_rtcp",
+        "../utility",
+        "//testing/gtest",
+      ]
+      public_configs = [ ":audio_device_config" ]
+    }
+  }
 }
 
 if (!build_with_chromium && is_android) {