Make AudioParameters a class instead of a struct

content/renderer/renderer_webkitplatformsupport_impl.cc

 // 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.
 
 #include "content/renderer/renderer_webkitplatformsupport_impl.h"
 
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/platform_file.h"
@@ skipping 571 matching lines @@
 double RendererWebKitPlatformSupportImpl::audioHardwareSampleRate() {
   return audio_hardware::GetOutputSampleRate();
 }
 
 size_t RendererWebKitPlatformSupportImpl::audioHardwareBufferSize() {
   return audio_hardware::GetOutputBufferSize();
 }
 
 WebAudioDevice*
 RendererWebKitPlatformSupportImpl::createAudioDevice(
-    size_t buffer_size,
-    unsigned channels,
-    double sample_rate,
+    size_t bufferSize,
+    unsigned numberOfChannels,
+    double sampleRate,
     WebAudioDevice::RenderCallback* callback) {
-  return new RendererWebAudioDeviceImpl(buffer_size,
-                                        channels,
-                                        sample_rate,
-                                        callback);
+  ChannelLayout layout = CHANNEL_LAYOUT_UNSUPPORTED;
+
+  // The |numberOfChannels| does not exactly identify the channel layout of the
+  // device. The switch statement below assigns a best guess to the channel
+  // layout based on number of channels.
+  // TODO(crogers): WebKit should give the channel layout instead of the hard

[vrk (LEFT CHROMIUM), 2012/03/09 20:59:32]

crogers: Note this TODO I assigned to you! What do you think?

+  // channel count.
+  switch (numberOfChannels) {
+    case 1:
+      layout = CHANNEL_LAYOUT_MONO;
+      break;
+    case 2:
+      layout = CHANNEL_LAYOUT_STEREO;
+      break;
+    case 3:
+      layout = CHANNEL_LAYOUT_2_1;
+      break;
+    case 4:
+      layout = CHANNEL_LAYOUT_4POINT0;

[tommi (sloooow) - chröme, 2012/03/10 10:11:32]

nit: what about using the underscore in all the value names instead of POINT? 
(i.e. make all follow the CHANNEL_LAYOUT_2_1 format)

[vrk (LEFT CHROMIUM), 2012/03/16 18:30:41]

SGTM. Looks like we were doing that to be consistent with FFmpeg's
POINT/underscore inconsistency (see revised ffmpeg_common.cc). Fixed to use
underscores!

+      break;
+    case 5:
+      layout = CHANNEL_LAYOUT_5POINT0;
+      break;
+    case 6:
+      layout = CHANNEL_LAYOUT_5POINT1;
+      break;
+    case 7:
+      layout = CHANNEL_LAYOUT_7POINT0;
+      break;
+    case 8:
+      layout = CHANNEL_LAYOUT_7POINT1;
+      break;
+  }

[scherkus (not reviewing), 2012/03/09 21:48:59]

we need a default case here -- perhaps stereo?

[vrk (LEFT CHROMIUM), 2012/03/16 18:30:41]

Done.

+
+  AudioParameters params(AudioParameters::AUDIO_PCM_LOW_LATENCY,
+                         layout,
+                         static_cast<int>(sampleRate),
+                         16,
+                         bufferSize);
+
+  return new RendererWebAudioDeviceImpl(params, callback);
 }
 
 //------------------------------------------------------------------------------
 
 WebKit::WebString
 RendererWebKitPlatformSupportImpl::signedPublicKeyAndChallengeString(
     unsigned key_size_index,
     const WebKit::WebString& challenge,
     const WebKit::WebURL& url) {
   std::string signed_public_key;
@@ skipping 42 matching lines @@
 RendererWebKitPlatformSupportImpl::createPeerConnectionHandler(
     WebKit::WebPeerConnectionHandlerClient* client) {
   WebFrame* web_frame = WebFrame::frameForCurrentContext();
   if (!web_frame)
     return NULL;
   RenderViewImpl* render_view = RenderViewImpl::FromWebView(web_frame->view());
   if (!render_view)
     return NULL;
   return render_view->CreatePeerConnectionHandler(client);
 }