Introduce AudioHardwareConfig for renderer side audio device info.

content/renderer/media/audio_hardware.h

-// Copyright (c) 2012 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_AUDIO_HARDWARE_H_
-#define CONTENT_RENDERER_MEDIA_AUDIO_HARDWARE_H_
-
-#include "base/basictypes.h"
-#include "content/common/content_export.h"
-#include "media/base/channel_layout.h"
-
-// This file contains static methods to query audio hardware properties from
-// the browser process.  Values are cached to avoid unnecessary round trips,
-// but the cache can be cleared if needed (currently only used by tests).
-
-namespace content {
-
-// Fetch the sample rate of the default audio output end point device.
-// Must be called from RenderThreadImpl::current().
-CONTENT_EXPORT int GetAudioOutputSampleRate();
-
-// Fetch the sample rate of the default audio input end point device.
-// Must be called from RenderThreadImpl::current().
-CONTENT_EXPORT int GetAudioInputSampleRate();
-
-// Fetch the buffer size we use for the default output device.
-// Must be called from RenderThreadImpl::current().
-// Must be used in conjunction with AUDIO_PCM_LOW_LATENCY.
-CONTENT_EXPORT size_t GetAudioOutputBufferSize();
-
-// Fetch the audio channel layout for the default input device.
-// Must be called from RenderThreadImpl::current().
-CONTENT_EXPORT media::ChannelLayout GetAudioInputChannelLayout();
-
-// Forces the next call to any of the Get functions to query the hardware
-// and repopulate the cache.
-CONTENT_EXPORT void ResetAudioCache();
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_MEDIA_AUDIO_HARDWARE_H_