Switch stream creation and closing in Chrome audio rendering from IPC to Mojo

content/browser/media/audio_output_impl.h

+// Copyright 2016 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_BROWSER_MEDIA_AUDIO_OUTPUT_IMPL_H_
+#define CONTENT_BROWSER_MEDIA_AUDIO_OUTPUT_IMPL_H_
+
+#include "base/callback.h"
+#include "content/browser/renderer_host/media/audio_renderer_host.h"
+#include "media/mojo/interfaces/audio_output.mojom.h"
+#include "mojo/public/cpp/bindings/interface_request.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+namespace content {
+class AudioOutputStreamImpl;
+
+// This class implements AudioOutput Mojo interface. It will be used
+// by the AudioOutputClient to perform operations on audio output streams.
+// AudioOutputClient is going to perform operations remotely and Mojo will
+// transfer them to AudioOutputImpl.
+// This class must always be accessed from the creation thread.
+class CONTENT_EXPORT AudioOutputImpl
+    : NON_EXPORTED_BASE(public media::mojom::AudioOutput) {
+ public:
+  explicit AudioOutputImpl(scoped_refptr<AudioRendererHost> audio_renderer_host,
+                           int render_frame_id,
+                           media::mojom::AudioOutputRequest request);
+
+  ~AudioOutputImpl() override;
+
+  // Creates a Mojo service.
+  static void CreateService(
+      scoped_refptr<AudioRendererHost> audio_renderer_host,
+      int render_frame_id,
+      media::mojom::AudioOutputRequest request);
+  // Initialized Mojo service on the IO thread. The service is bound to the
+  // IO thread so future Mojo calls performed by the AudioOutputClient to the
+  // AudioOutput interface will be run on that thread.
+  // There are a lot of dependencies used in audio output that require to be
+  // called on the IO thread, this is why we initialize Mojo service on this
+  // thread. There is a plan to enable these dependencies to run on another
+  // thread and move the Mojo service to this thread as IO thread is very
+  // performance sensitive and we want to move stuff off it.
+  static void CreateServiceOnIOThread(
+      scoped_refptr<AudioRendererHost> audio_renderer_host,
+      int render_frame_id,
+      media::mojom::AudioOutputRequest request);
+
+  // Called by AudioRendererHost::DoCompleteCreation to create the streams.
+  virtual media::mojom::AudioOutputStreamPtr StreamFactory(
+      int stream_id,
+      int render_frame_id,
+      AudioRendererHost* audio_renderer_host);
+
+  virtual bool RemoveStream(int stream_id);
+
+ private:
+  friend class AudioOutputImplTest;
+  FRIEND_TEST_ALL_PREFIXES(AudioOutputImplTest, CreateStream);
+  FRIEND_TEST_ALL_PREFIXES(AudioOutputImplTest, StreamFactory);
+  FRIEND_TEST_ALL_PREFIXES(AudioOutputImplTest, RemoveStream);
+  // AudioOutput interface implementation.
+  void CreateStream(int stream_id,
+                    const media::AudioParameters& params,
+                    const CreateStreamCallback& callback) override;
+
+  scoped_refptr<AudioRendererHost> audio_renderer_host_;
+  int render_frame_id_;
+  mojo::Binding<AudioOutput> binding_;
+  std::map<int, std::unique_ptr<AudioOutputStreamImpl>> stream_impls_;
+
+  base::Callback<AudioOutputStreamImpl*(
+      media::mojom::AudioOutputStreamRequest request,
+      int stream_id,
+      int renderer_frame_id,
+      AudioRendererHost* audio_renderer_host)>
+      factory_;
+  DISALLOW_COPY_AND_ASSIGN(AudioOutputImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_AUDIO_OUTPUT_IMPL_H_