Adds support for 16kHz input sample rate and mono channel config. in WebRTC.

content/browser/renderer_host/render_message_filter.cc

Index: content/browser/renderer_host/render_message_filter.cc
diff --git a/content/browser/renderer_host/render_message_filter.cc b/content/browser/renderer_host/render_message_filter.cc
index 6429524753e6e0c3aea04b8945306da021479989..23e4e2596b1cb08797e1c4240c9ccbe542e7fd1a 100644
--- a/content/browser/renderer_host/render_message_filter.cc
+++ b/content/browser/renderer_host/render_message_filter.cc
@@ -380,6 +380,8 @@ bool RenderMessageFilter::OnMessageReceived(const IPC::Message& message,
                         OnGetHardwareInputSampleRate)
     IPC_MESSAGE_HANDLER(ViewHostMsg_GetHardwareSampleRate,
                         OnGetHardwareSampleRate)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_GetHardwareInputChannelCount,
+                        OnGetHardwareInputChannelCount)
     IPC_MESSAGE_HANDLER(ViewHostMsg_MediaLogEvent, OnMediaLogEvent)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP_EX()
@@ -673,6 +675,10 @@ void RenderMessageFilter::OnGetHardwareSampleRate(double* sample_rate) {
   *sample_rate = media::GetAudioHardwareSampleRate();
 }
 
+void RenderMessageFilter::OnGetHardwareInputChannelCount(uint32* channels) {
+  *channels = static_cast<uint32>(media::GetAudioInputHardwareChannelCount());
+}
+
 void RenderMessageFilter::OnDownloadUrl(const IPC::Message& message,
                                         const GURL& url,
                                         const GURL& referrer,