Adding ChannelController to audio network adaptor.

webrtc/modules/audio_coding/audio_network_adaptor/channel_controller.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_AUDIO_NETWORK_ADAPTOR_CHANNEL_CONTROLLER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_CHANNEL_CONTROLLER_H_
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_coding/audio_network_adaptor/controller.h"
+
+namespace webrtc {
+
+class ChannelController final : public Controller {
+ public:
+  struct Config {
+    Config(size_t num_encoder_channels,
+           size_t intial_channels_to_encode,
+           int channel_1_to_2_bandwidth_bps,
+           int channel_2_to_1_bandwidth_bps);
+    size_t num_encoder_channels;
+    size_t intial_channels_to_encode;
+    // Uplink bandwidth above which the number of encoded channels should switch
+    // from 1 to 2.
+    int channel_1_to_2_bandwidth_bps;
+    // Uplink bandwidth below which the number of encoded channels should switch
+    // from 2 to 1.
+    int channel_2_to_1_bandwidth_bps;
+  };
+
+  explicit ChannelController(const Config& config);
+
+  void MakeDecision(const NetworkMetrics& metrics,
+                    AudioNetworkAdaptor::EncoderRuntimeConfig* config) override;
+
+ private:
+  const Config config_;
+  size_t channels_to_encode_;
+  RTC_DISALLOW_COPY_AND_ASSIGN(ChannelController);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_CHANNEL_CONTROLLER_H_