Implement renderer AudioDevice API for low-latency audio output...

chrome/renderer/renderer_webaudiodevice_impl.cc

+// Copyright (c) 2010 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.
+
+#include "chrome/renderer/renderer_webaudiodevice_impl.h"
+
+using WebKit::WebAudioDevice;
+using WebKit::WebVector;
+
+RendererWebAudioDeviceImpl::RendererWebAudioDeviceImpl(size_t buffer_size,
+    int channels, double sample_rate, WebAudioDevice::RenderCallback* callback)
+    : client_callback_(callback) {
+  audio_device_.reset(
+      new AudioDevice(buffer_size, channels, sample_rate, this));
+}
+
+RendererWebAudioDeviceImpl::~RendererWebAudioDeviceImpl() {
+  stop();
+}
+
+void RendererWebAudioDeviceImpl::start() {
+  audio_device_->Start();
+}
+
+void RendererWebAudioDeviceImpl::stop() {
+  audio_device_->Stop();
+}
+
+void RendererWebAudioDeviceImpl::Render(const std::vector<float*>& audio_data,
+                                size_t number_of_frames) {
+  // Make the client callback to get rendered audio.
+  DCHECK(client_callback_);
+  if (client_callback_) {
+    // Wrap the pointers using WebVector.
+    WebVector<float*> web_audio_data(audio_data.size());
+    for (size_t i = 0; i < audio_data.size(); ++i)
+      web_audio_data[i] = audio_data[i];
+
+    client_callback_->render(web_audio_data, number_of_frames);
+  }
+}