Introduce CodecManager and move code from AudioCodingModuleImpl

This change essentially divides AudioCodingModuleImpl into two parts:
one is the code related to managing codecs, now moved into CodecManager,
and the other is what remains in AudioCodingModuleImpl.

This change also removes AudioCodingModuleImpl::InitializeSender. The
function was essentially no-op, since it was always called immediately
after construction.

COAUTHOR=kwiberg@webrtc.org
BUG=4228
R=minyue@webrtc.org, tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/51469004

Cr-Commit-Position: refs/heads/master@{#8893}

webrtc/modules/audio_coding/main/acm2/codec_manager.h

@@ -0,0 +1,101 @@
+/*
+ *  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.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_MAIN_ACM2_CODEC_MANAGER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_MAIN_ACM2_CODEC_MANAGER_H_
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/thread_checker.h"
+#include "webrtc/modules/audio_coding/main/acm2/acm_codec_database.h"
+#include "webrtc/modules/audio_coding/main/interface/audio_coding_module_typedefs.h"
+#include "webrtc/common_types.h"
+
+namespace webrtc {
+
+class AudioDecoder;
+
+namespace acm2 {
+
+class ACMGenericCodec;
+class AudioCodingModuleImpl;
+
+class CodecManager final {
+ public:
+  explicit CodecManager(AudioCodingModuleImpl* acm);
+  ~CodecManager();
+
+  int RegisterSendCodec(const CodecInst& send_codec);
+
+  int SendCodec(CodecInst* current_codec) const;
+
+  int RegisterReceiveCodec(const CodecInst& receive_codec);
+
+  bool SetCopyRed(bool enable);
+
+  int SetVAD(bool enable_dtx, bool enable_vad, ACMVADMode mode);
+
+  void VAD(bool* dtx_enabled, bool* vad_enabled, ACMVADMode* mode) const;
+
+  int SetCodecFEC(bool enable_codec_fec);
+
+  bool stereo_send() const { return stereo_send_; }
+
+  bool red_enabled() const { return red_enabled_; }
+
+  bool codec_fec_enabled() const { return codec_fec_enabled_; }
+
+  ACMGenericCodec* current_encoder() { return current_encoder_; }
+
+  const ACMGenericCodec* current_encoder() const { return current_encoder_; }
+
+ private:
+  void SetCngPayloadType(int sample_rate_hz, int payload_type);
+
+  void SetRedPayloadType(int sample_rate_hz, int payload_type);
+
+  // Get a pointer to AudioDecoder of the given codec. For some codecs, e.g.
+  // iSAC, encoding and decoding have to be performed on a shared
+  // codec-instance. By calling this method, we get the codec-instance that ACM
+  // owns, then pass that to NetEq. This way, we perform both encoding and
+  // decoding on the same codec-instance. Furthermore, ACM would have control
+  // over decoder functionality if required. If |codec| does not share an
+  // instance between encoder and decoder, the |*decoder| is set NULL.
+  // The field ACMCodecDB::CodecSettings.owns_decoder indicates that if a
+  // codec owns the decoder-instance. For such codecs |*decoder| should be a
+  // valid pointer, otherwise it will be NULL.
+  int GetAudioDecoder(const CodecInst& codec,
+                      int codec_id,
+                      int mirror_id,
+                      AudioDecoder** decoder);
+
+  AudioCodingModuleImpl* acm_;
+  rtc::ThreadChecker thread_checker_;
+  uint8_t cng_nb_pltype_;
+  uint8_t cng_wb_pltype_;
+  uint8_t cng_swb_pltype_;
+  uint8_t cng_fb_pltype_;
+  uint8_t red_nb_pltype_;
+  bool stereo_send_;
+  bool vad_enabled_;
+  bool dtx_enabled_;
+  ACMVADMode vad_mode_;
+  ACMGenericCodec* current_encoder_;
+  CodecInst send_codec_inst_;
+  bool red_enabled_;
+  bool codec_fec_enabled_;
+  ACMGenericCodec* codecs_[ACMCodecDB::kMaxNumCodecs];
+  int mirror_codec_idx_[ACMCodecDB::kMaxNumCodecs];
+
+  DISALLOW_COPY_AND_ASSIGN(CodecManager);
+};
+
+}  // namespace acm2
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_MAIN_ACM2_CODEC_MANAGER_H_