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

content/renderer/media/audio_hardware.h

Index: content/renderer/media/audio_hardware.h
diff --git a/content/renderer/media/audio_hardware.h b/content/renderer/media/audio_hardware.h
index c6030733a11697d2b316ef3a3c5d0f10f7cc8db1..ea9a28a61ed57b4f7b8c0c293b34ef93e3d62ac2 100644
--- a/content/renderer/media/audio_hardware.h
+++ b/content/renderer/media/audio_hardware.h
@@ -26,6 +26,10 @@ CONTENT_EXPORT double GetInputSampleRate();
 // Must be called from RenderThreadImpl::current().
 CONTENT_EXPORT size_t GetOutputBufferSize();
 
+// Fetch the number of audio channels for the default input device.
+// Must be called from RenderThreadImpl::current().
+CONTENT_EXPORT uint32 GetInputChannelCount();
+
 // Forces the next call to any of the Get functions to query the hardware
 // and repopulate the cache.
 CONTENT_EXPORT void ResetCache();