GN: Refactor webrtc_nonparallel_tests and audio_tests to avoid crossing package boundaries.

webrtc/audio/utility/BUILD.gn

 # Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 import("../../build/webrtc.gni")
 
 group("utility") {
   public_deps = [
     ":audio_frame_operations",
   ]
 }
 
 rtc_static_library("audio_frame_operations") {
   sources = [
     "audio_frame_operations.cc",
     "audio_frame_operations.h",
   ]
 
   deps = [
     "../..:webrtc_common",
     "../../base:rtc_base_approved",
     "../../modules/audio_coding:audio_format_conversion",
   ]
 }
+
+if (rtc_include_tests) {
+  rtc_source_set("utility_tests") {
+    testonly = true
+    sources = [
+      "audio_frame_operations_unittest.cc",
+    ]
+    deps = [
+      ":audio_frame_operations",
+      "//testing/gtest",
+    ]
+    if (!build_with_chromium && is_clang) {
+      # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
+      suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
+    }
+  }
+}