Support audio output device enumeration and selection in PPAPI

content/renderer/pepper/pepper_audio_output_host.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 CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_OUTPUT_HOST_H_
+#define CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_OUTPUT_HOST_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/memory/shared_memory.h"
+#include "base/sync_socket.h"
+#include "content/public/renderer/plugin_instance_throttler.h"
+#include "content/renderer/pepper/pepper_device_enumeration_host_helper.h"
+#include "ipc/ipc_platform_file.h"
+#include "ppapi/c/ppb_audio_config.h"
+#include "ppapi/host/host_message_context.h"
+#include "ppapi/host/resource_host.h"
+
+namespace content {
+class PepperPlatformAudioOutput;
+class RendererPpapiHostImpl;
+
+class PepperAudioOutputHost : public ppapi::host::ResourceHost,
+                              public PluginInstanceThrottler::Observer {
+ public:
+  PepperAudioOutputHost(RendererPpapiHostImpl* host,
+                        PP_Instance instance,
+                        PP_Resource resource);
+  ~PepperAudioOutputHost() override;
+
+  int32_t OnResourceMessageReceived(
+      const IPC::Message& msg,
+      ppapi::host::HostMessageContext* context) override;
+
+  // Called when the stream is created.
+  void StreamCreated(base::SharedMemoryHandle shared_memory_handle,
+                     size_t shared_memory_size,
+                     base::SyncSocket::Handle socket);
+  void StreamCreationFailed();
+  void SetVolume(double volume);
+ private:
+  int32_t OnOpen(ppapi::host::HostMessageContext* context,
+                 const std::string& device_id,
+                 PP_AudioSampleRate sample_rate,
+                 uint32_t sample_frame_count);
+  int32_t OnStartOrStop(ppapi::host::HostMessageContext* context,
+                 bool playback);
+  int32_t OnClose(ppapi::host::HostMessageContext* context);
+
+  void OnOpenComplete(int32_t result,
+                      base::SharedMemoryHandle shared_memory_handle,
+                      size_t shared_memory_size,
+                      base::SyncSocket::Handle socket_handle);
+
+  int32_t GetRemoteHandles(
+      const base::SyncSocket& socket,
+      const base::SharedMemory& shared_memory,
+      IPC::PlatformFileForTransit* remote_socket_handle,
+      base::SharedMemoryHandle* remote_shared_memory_handle);
+
+  void Close();
+
+  void SendOpenReply(int32_t result);
+
+  // PluginInstanceThrottler::Observer implementation.
+  void OnThrottleStateChange() override;
+
+  // Starts the deferred playback and unsubscribes from the throttler.
+  void StartDeferredPlayback();
+
+  // Non-owning pointer.
+  RendererPpapiHostImpl* renderer_ppapi_host_;
+
+  ppapi::host::ReplyMessageContext open_context_;
+
+  // Audio output object that we delegate audio IPC through.
+  // We don't own this pointer but are responsible for calling Shutdown on it.
+  PepperPlatformAudioOutput* audio_output_;
+
+  // Stream is playing, but throttled due to Plugin Power Saver.
+  bool playback_throttled_;
+
+  PepperDeviceEnumerationHostHelper enumeration_helper_;
+
+  DISALLOW_COPY_AND_ASSIGN(PepperAudioOutputHost);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_OUTPUT_HOST_H_