WebRtcVoiceEngine: Use AudioDecoderFactory to generate recv codecs.

webrtc/media/engine/payload_type_mapper.h

Index: webrtc/media/engine/payload_type_mapper.h
diff --git a/webrtc/media/engine/payload_type_mapper.h b/webrtc/media/engine/payload_type_mapper.h
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+++ b/webrtc/media/engine/payload_type_mapper.h
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+/*
+ *  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_MEDIA_ENGINE_PAYLOAD_TYPE_MAPPER_H_
+#define WEBRTC_MEDIA_ENGINE_PAYLOAD_TYPE_MAPPER_H_
+
+#include <map>
+#include <set>
+
+#include "webrtc/base/optional.h"
+#include "webrtc/media/base/codec.h"
+#include "webrtc/modules/audio_coding/codecs/audio_format.h"
+
+namespace cricket {
+
+class PayloadTypeMapper {
+ public:
+  PayloadTypeMapper();
+  ~PayloadTypeMapper();
+
+  // Finds the current payload type for |format| or assigns a new one, if no
+  // current mapping exists. Will return an empty value if it was unable to
+  // create a mapping, i.e. if all dynamic payload type ids have been used up.
+  rtc::Optional<int> GetMappingFor(const webrtc::SdpAudioFormat& format);
+
+  // Finds the current payload type for |format|, if any. Returns an empty value
+  // if no payload type mapping exists for the format.
+  rtc::Optional<int> FindMappingFor(const webrtc::SdpAudioFormat& format) const;
+
+  // Like GetMappingFor, but fills in an AudioCodec structure with the necessary
+  // information instead.
+  rtc::Optional<AudioCodec> ToAudioCodec(const webrtc::SdpAudioFormat& format);
+
+ private:
+  struct SdpAudioFormatOrdering {
+    bool operator()(const webrtc::SdpAudioFormat& a,
+                    const webrtc::SdpAudioFormat& b) const;
+  };
+
+  int next_unused_payload_type_;
+  int max_payload_type_;
+  std::map<webrtc::SdpAudioFormat, int, SdpAudioFormatOrdering> mappings_;
+  std::set<int> used_payload_types_;
+};
+
+}  // namespace cricket
+#endif  // WEBRTC_MEDIA_ENGINE_PAYLOAD_TYPE_MAPPER_H_