Add mojo interface+impl creation of audio streams.

content/browser/renderer_host/media/audio_output_stream_factory_context.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_BROWSER_RENDERER_HOST_MEDIA_AUDIO_OUTPUT_STREAM_FACTORY_CONTEXT_H_
+#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_OUTPUT_STREAM_FACTORY_CONTEXT_H_
+
+#include <memory>
+#include <string>
+
+#include "content/browser/renderer_host/media/audio_output_authorization_handler.h"
+#include "content/common/content_export.h"
+#include "media/audio/audio_output_delegate.h"
+
+namespace media {
+class AudioParameters;
+}
+
+namespace content {
+
+namespace mojom {
+class RendererAudioOutputStreamFactory;
+}  // namespace mojom
+
+// AudioOutputStreamFactoryContext provides functions common to all
+// AudioOutputFactory instances for a single renderer process.
+class CONTENT_EXPORT AudioOutputStreamFactoryContext {

[o1ka, 2017/03/21 16:20:17]

I'd prefer RendererAudioOutputStreamFactoryContext for the name, it would be
more descriptive.

[Max Morin, 2017/03/22 13:18:29]

Done.

+ public:
+  virtual ~AudioOutputStreamFactoryContext() {}
+
+  using AuthorizationCompletedCallback =
+      AudioOutputAuthorizationHandler::AuthorizationCompletedCallback;
+
+  virtual int GetRenderProcessId() const = 0;
+  virtual const std::string& GetSalt() const = 0;
+
+  // Called to request access to a device on behalf of the renderer.
+  virtual void RequestDeviceAuthorization(
+      int render_frame_id,
+      int session_id,
+      const std::string& device_id,
+      const url::Origin& security_origin,
+      AuthorizationCompletedCallback cb) const = 0;
+
+  virtual std::unique_ptr<media::AudioOutputDelegate> CreateDelegate(
+      const std::string& unique_device_id,
+      int render_frame_id,
+      const media::AudioParameters& params,
+      media::AudioOutputDelegate::EventHandler* handler) = 0;
+
+  // Should be called by a service when it's done or has encountered an error.
+  // Will delete |service|.
+  virtual void OnFactoryFinished(
+      mojom::RendererAudioOutputStreamFactory* service) = 0;
+};
+
+}  // namespace content
+
+#endif  //  CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_OUTPUT_STREAM_FACTORY_CONTEXT_H_