Move AudioDecoder and related stuff to the api/ directory

webrtc/modules/audio_coding/codecs/audio_decoder_factory.h

-/*
- *  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.
- */
-
-#ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_DECODER_FACTORY_H_
-#define WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_DECODER_FACTORY_H_
-
-#include <memory>
-#include <vector>
-
-#include "webrtc/base/atomicops.h"
-#include "webrtc/base/refcount.h"
-#include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
-#include "webrtc/modules/audio_coding/codecs/audio_format.h"
-
-namespace webrtc {
-
-// A factory that creates AudioDecoders.
-// NOTE: This class is still under development and may change without notice.
-class AudioDecoderFactory : public rtc::RefCountInterface {
- public:
-  virtual std::vector<AudioCodecSpec> GetSupportedDecoders() = 0;
-
-  virtual bool IsSupportedDecoder(const SdpAudioFormat& format) = 0;
-
-  virtual std::unique_ptr<AudioDecoder> MakeAudioDecoder(
-      const SdpAudioFormat& format) = 0;
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_DECODER_FACTORY_H_