Move AudioCodingModuleImpl to anonymous namespace in audio_coding_module.cc

webrtc/modules/audio_coding/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")
 import("audio_coding.gni")
@@ skipping 77 matching lines @@
 }
 
 source_set("audio_coding") {
   sources = [
     "acm2/acm_common_defs.h",
     "acm2/acm_receiver.cc",
     "acm2/acm_receiver.h",
     "acm2/acm_resampler.cc",
     "acm2/acm_resampler.h",
     "acm2/audio_coding_module.cc",
-    "acm2/audio_coding_module_impl.cc",
-    "acm2/audio_coding_module_impl.h",
     "acm2/call_statistics.cc",
     "acm2/call_statistics.h",
     "acm2/codec_manager.cc",
     "acm2/codec_manager.h",
     "acm2/initial_delay_manager.cc",
     "acm2/initial_delay_manager.h",
     "include/audio_coding_module.h",
     "include/audio_coding_module_typedefs.h",
   ]
 
@@ skipping 906 matching lines @@
       configs -= [ "//build/config/clang:find_bad_constructs" ]
     }
 
     deps = [
       "../../common_audio",
       "../../test:rtp_test_utils",
       "../rtp_rtcp",
     ]
   }
 }