Don't link with audio codecs that we don't use

webrtc/modules/audio_coding/neteq/audio_decoder_impl.h

 /*
  *  Copyright (c) 2012 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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ_AUDIO_DECODER_IMPL_H_
 #define WEBRTC_MODULES_AUDIO_CODING_NETEQ_AUDIO_DECODER_IMPL_H_
 
 #include <assert.h>
 
-#ifndef AUDIO_DECODER_UNITTEST
-// If this is compiled as a part of the audio_deoder_unittest, the codec
-// selection is made in the gypi file instead of in engine_configurations.h.
 #include "webrtc/engine_configurations.h"
-#endif
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
 #include "webrtc/modules/audio_coding/codecs/cng/include/webrtc_cng.h"
 #ifdef WEBRTC_CODEC_G722
 #include "webrtc/modules/audio_coding/codecs/g722/include/g722_interface.h"
 #endif
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
@@ skipping 66 matching lines @@
 // Returns the sample rate for |codec_type|.
 int CodecSampleRateHz(NetEqDecoder codec_type);
 
 // Creates an AudioDecoder object of type |codec_type|. Returns NULL for for
 // unsupported codecs, and when creating an AudioDecoder is not applicable
 // (e.g., for RED and DTMF/AVT types).
 AudioDecoder* CreateAudioDecoder(NetEqDecoder codec_type);
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_AUDIO_DECODER_IMPL_H_