Support audio output device enumeration and selection in PPAPI

ppapi/cpp/dev/audio_output_dev.h

+// Copyright (c) 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PPAPI_CPP_DEV_AUDIO_OUTPUT_DEV_H_
+#define PPAPI_CPP_DEV_AUDIO_OUTPUT_DEV_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "ppapi/c/dev/ppb_audio_output_dev.h"
+#include "ppapi/cpp/audio_config.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/dev/device_ref_dev.h"
+#include "ppapi/cpp/resource.h"
+
+namespace pp {
+
+class InstanceHandle;
+
+class AudioOutput_Dev : public Resource {
+ public:
+  // An empty constructor for an AudioOutput resource.
+  AudioOutput_Dev();
+
+  // Constructor to create an audio output resource.
+  explicit AudioOutput_Dev(const InstanceHandle& instance);
+
+  virtual ~AudioOutput_Dev();
+
+  // Static function for determining whether the browser supports the required
+  // AudioOutput interface.
+  //
+  // @return true if the interface is available, false otherwise.
+  static bool IsAvailable();
+
+  int32_t EnumerateDevices(
+      const CompletionCallbackWithOutput<std::vector<DeviceRef_Dev> >& cb);
+
+  int32_t MonitorDeviceChange(PP_MonitorDeviceChangeCallback callback,
+                              void* user_data);
+
+  // If |device_ref| is null (i.e., is_null() returns true), the default device
+  // will be used.
+  int32_t Open(const DeviceRef_Dev& device_ref,
+               const AudioConfig& config,
+               PPB_AudioOutput_Callback audio_output_callback,
+               void* user_data,
+               const CompletionCallback& callback);
+
+  // Getter function for returning the internal <code>PPB_AudioConfig</code>
+  // struct.
+  //
+  // @return A mutable reference to the PPB_AudioConfig struct.
+  AudioConfig& config() { return config_; }
+
+  // Getter function for returning the internal <code>PPB_AudioConfig</code>
+  // struct.
+  //
+  // @return A const reference to the internal <code>PPB_AudioConfig</code>
+  // struct.
+  const AudioConfig& config() const { return config_; }
+
+  // StartPlayback() starts playback of audio.
+  //
+  // @return true if successful, otherwise false.
+  bool StartPlayback();
+
+  // StopPlayback stops playback of audio.
+  //
+  // @return true if successful, otherwise false.
+  bool StopPlayback();
+
+  // Close closes the audio output device.
+  void Close();
+
+ private:
+  AudioConfig config_;
+};
+
+}  // namespace pp
+
+#endif  // PPAPI_CPP_DEV_AUDIO_OUTPUT_DEV_H_