Revert of Revert of Remove the last piece of deprecated synchronous IO code.

content/renderer/renderer_webkitplatformsupport_impl.cc

Index: content/renderer/renderer_webkitplatformsupport_impl.cc
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.cc b/content/renderer/renderer_webkitplatformsupport_impl.cc
index c150e0c624ae7bda6806483818d2a117c2a8e005..bb61a0ec008a9b74ab9205fd4602fdb21390670d 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -743,8 +743,7 @@
 
   media::AudioParameters params(
       media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
-      layout, input_channels,
-      static_cast<int>(sample_rate), 16, buffer_size,
+      layout, static_cast<int>(sample_rate), 16, buffer_size,
       media::AudioParameters::NO_EFFECTS);
 
   return new RendererWebAudioDeviceImpl(params, callback, session_id);