Added webrtc/audio/utility directory and empty GN target.

webrtc/audio/BUILD.gn

 # Copyright (c) 2015 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")
 
@@ skipping 19 matching lines @@
   deps = [
     "..:webrtc_common",
     "../api:audio_mixer_api",
     "../api:call_api",
     "../base:rtc_base_approved",
     "../common_audio",
     "../modules/audio_device",
     "../modules/audio_processing",
     "../system_wrappers",
     "../voice_engine",
+    "utility",  # Bogus dep, needed for landing
+                # codereview.webrtc.org/2424173003 without breaking
+                # internal projects. See
+                # bugs.webrtc.org/6548. TODO(aleloi): remove dependency
+                # when codereview.webrtc.org/2424173003 has landed.
   ]
 }
 if (rtc_include_tests) {
   rtc_source_set("audio_tests") {
     testonly = true
     sources = [
       "audio_receive_stream_unittest.cc",
       "audio_send_stream_unittest.cc",
       "audio_state_unittest.cc",
     ]
     deps = [
       ":audio",
       "../api:mock_audio_mixer",
       "../base:rtc_base_approved",
       "../modules/audio_device:mock_audio_device",
       "../modules/audio_mixer:audio_mixer_impl",
       "../test:test_common",
       "//testing/gmock",
       "//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" ]
     }
   }
 }