Update AudioProcessing::Create docs.

TBR=bjornv

Review URL: https://webrtc-codereview.appspot.com/8039004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5488 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index cdbadb9..09d4cd4 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -136,12 +136,13 @@
 //
 class AudioProcessing : public Module {
  public:
-  // Creates a APM instance, with identifier |id|. Use one instance for every
-  // primary audio stream requiring processing. On the client-side, this would
-  // typically be one instance for the near-end stream, and additional instances
-  // for each far-end stream which requires processing. On the server-side,
-  // this would typically be one instance for every incoming stream.
+  // Creates an APM instance. Use one instance for every primary audio stream
+  // requiring processing. On the client-side, this would typically be one
+  // instance for the near-end stream, and additional instances for each far-end
+  // stream which requires processing. On the server-side, this would typically
+  // be one instance for every incoming stream.
   static AudioProcessing* Create();
+  // Allows passing in an optional configuration at create-time.
   static AudioProcessing* Create(const Config& config);
   // TODO(ajm): Deprecated; remove all calls to it.
   static AudioProcessing* Create(int id);