Add ExperimentalNs support in Config

R=andrew@webrtc.org, xians@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/17829004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6567 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 77c3f3a..1e494d1 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -73,6 +73,14 @@
   bool enabled;
 };
 
+// Use to enable experimental noise suppression. It can be set in the
+// constructor or using AudioProcessing::SetExtraOptions().
+struct ExperimentalNs {
+  ExperimentalNs() : enabled(false) {}
+  explicit ExperimentalNs(bool enabled) : enabled(enabled) {}
+  bool enabled;
+};
+
 static const int kAudioProcMaxNativeSampleRateHz = 32000;
 
 // The Audio Processing Module (APM) provides a collection of voice processing