Renderer side audio device change wip...

content/renderer/media/renderer_audio_hardware_config.h

+// Copyright (c) 2013 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_RENDERER_AUDIO_HARDWARE_CONFIG_H_
+#define CONTENT_RENDERER_MEDIA_RENDERER_AUDIO_HARDWARE_CONFIG_H_
+
+#include "base/compiler_specific.h"
+#include "base/synchronization/lock.h"
+#include "content/common/content_export.h"
+#include "media/base/audio_hardware_config.h"
+
+namespace content {
+
+// Provides access to the audio hardware configuration from the renderer side.
+class CONTENT_EXPORT RendererAudioHardwareConfig
+    : public media::AudioHardwareConfig {
+ public:
+  // Must be constructed on the render thread.  RendererAudioHardwareConfig
+  // sends a synchronous IPC to retrieve the audio hardware configuration; once
+  // complete accessors and updaters may be called from any thread.
+  RendererAudioHardwareConfig();
+  virtual ~RendererAudioHardwareConfig();
+
+  // Accessors for the currently cached hardware configuration.  Safe to call
+  // from any thread.
+  virtual int GetOutputBufferSize() OVERRIDE;
+  virtual int GetOutputSampleRate() OVERRIDE;
+  virtual int GetInputSampleRate() OVERRIDE;
+  virtual media::ChannelLayout GetInputChannelLayout() OVERRIDE;
+
+  // Allows callers to update the cached values for either input or output.  The
+  // values are paired under the assumption that these values will only be set
+  // after an input or output device change respectively.  Safe to call from
+  // any thread.
+  void UpdateInputConfig(int sample_rate, media::ChannelLayout channel_layout);
+  void UpdateOutputConfig(int buffer_size, int sample_rate);
+
+ private:
+  // Cached values; access is protected by |config_lock_|.
+  base::Lock config_lock_;
+  int output_buffer_size_;
+  int output_sample_rate_;
+  int input_sample_rate_;
+  media::ChannelLayout input_channel_layout_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_RENDERER_AUDIO_HARDWARE_CONFIG_H_