Expose NetEq playout mode off through VoiceEngine.

BUG=

Review URL: https://webrtc-codereview.appspot.com/971016

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@3272 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/common_types.h b/common_types.h
index 52cc075..b21fc1b 100644
--- a/common_types.h
+++ b/common_types.h
@@ -430,6 +430,9 @@
     // Optimzed for decodability of fax signals rather than for perceived audio
     // quality.
     kNetEqFax = 2,
+    // Minimal buffer management. Inserts zeros for lost packets and during
+    // buffer increases.
+    kNetEqOff = 3,
 };
 
 enum NetEqBgnModes          // NetEQ Background Noise (BGN) configurations