Add a mojo implementation of AudioOutputIPC.

content/renderer/media/mojo_audio_output_ipc.h

+// Copyright 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_MEDIA_MOJO_AUDIO_OUTPUT_IPC_H_
+#define CONTENT_RENDERER_MEDIA_MOJO_AUDIO_OUTPUT_IPC_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "content/common/content_export.h"
+#include "content/common/media/renderer_audio_output_stream_factory.mojom.h"
+#include "media/audio/audio_output_ipc.h"
+
+namespace content {
+
+// MojoAudioOutputIPC is a renderer-side class for handling creation,
+// initialization and control of an output stream. May only be used on a single
+// thread.
+class CONTENT_EXPORT MojoAudioOutputIPC : public media::AudioOutputIPC {
+ public:
+  using FactoryAccessor =
+      base::RepeatingCallback<mojom::RendererAudioOutputStreamFactory*()>;
+
+  // |factory_accessor| is required to provide a
+  // RendererAudioOutputStreamFactory* if IPC is possible.
+  explicit MojoAudioOutputIPC(FactoryAccessor factory_accessor);

[DaleCurtis, 2017/05/24 01:36:54]

Typically we end callbacks types with CB for clarity.

[Max Morin, 2017/05/30 14:17:11]

Done.

+
+  ~MojoAudioOutputIPC() override;
+
+  // AudioOutputIPC implementation.
+  void RequestDeviceAuthorization(media::AudioOutputIPCDelegate* delegate,

[DaleCurtis, 2017/05/24 01:36:54]

Technically I/O parameters should be last. I realize this is an old API though
so no need to change it here. Ditto on the method below.

[Max Morin, 2017/05/30 14:17:11]

Yes, maybe we can revisit the AudioOutputIPC interface later, but doing it now
would also require changing AudioMessageFilter so I'll leave this as it is.

+                                  int session_id,
+                                  const std::string& device_id,
+                                  const url::Origin& security_origin) override;
+  void CreateStream(media::AudioOutputIPCDelegate* delegate,
+                    const media::AudioParameters& params) override;
+  void PlayStream() override;
+  void PauseStream() override;
+  void CloseStream() override;
+  void SetVolume(double volume) override;
+
+ private:
+  using AuthorizationCallback = mojom::RendererAudioOutputStreamFactory::

[DaleCurtis, 2017/05/24 01:36:55]

AuthorizationCB is sufficient if you want.

[Max Morin, 2017/05/30 14:17:11]

Done.

+      RequestDeviceAuthorizationCallback;
+
+  bool AuthorizationRequested();
+  bool StreamCreationRequested();
+  media::mojom::AudioOutputStreamProviderRequest MakeProviderRequest();
+
+  // Tries to acquire a RendererAudioOutputStreamFactory, returns true on
+  // success. On failure, |this| has been deleted, so returning immediately
+  // is required.
+  bool DoRequestDeviceAuthorization(int session_id,
+                                    const std::string& device_id,
+                                    AuthorizationCallback callback);
+
+  void RecievedDeviceAuthorization(media::OutputDeviceStatus status,
+                                   const media::AudioParameters& params,
+                                   const std::string& device_id) const;
+
+  void StreamCreated(mojo::ScopedSharedBufferHandle shared_memory,
+                     mojo::ScopedHandle socket);
+
+  const FactoryAccessor factory_accessor_;
+
+  THREAD_CHECKER(thread_checker_);
+  media::mojom::AudioOutputStreamProviderPtr stream_provider_;
+  media::mojom::AudioOutputStreamPtr stream_;
+  media::AudioOutputIPCDelegate* delegate_ = nullptr;
+
+  // To make sure we don't send an "authorization completed" callback for a
+  // stream after it's closed, we use this weak factory.
+  base::WeakPtrFactory<MojoAudioOutputIPC> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoAudioOutputIPC);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_MOJO_AUDIO_OUTPUT_IPC_H_