GN: Change rtc_source_set targets --> rtc_static_library

webrtc/modules/utility/BUILD.gn

 # Copyright (c) 2014 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")
 
-rtc_source_set("utility") {
+rtc_static_library("utility") {
   sources = [
     "include/audio_frame_operations.h",
     "include/file_player.h",
     "include/file_recorder.h",
     "include/helpers_android.h",
     "include/jvm_android.h",
     "include/process_thread.h",
     "source/audio_frame_operations.cc",
     "source/coder.cc",
     "source/coder.h",
@@ skipping 18 matching lines @@
 
   deps = [
     "../..:webrtc_common",
     "../../base:rtc_task_queue",
     "../../common_audio",
     "../../system_wrappers",
     "../audio_coding",
     "../media_file",
   ]
 }