NetEq changes.

BUG=
R=henrik.lundin@webrtc.org, minyue@webrtc.org, tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9859005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5889 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq4/sync_buffer.h b/webrtc/modules/audio_coding/neteq4/sync_buffer.h
index e1e5daf..0659f19 100644
--- a/webrtc/modules/audio_coding/neteq4/sync_buffer.h
+++ b/webrtc/modules/audio_coding/neteq4/sync_buffer.h
@@ -78,7 +78,8 @@
   // created.
   void Flush();
 
-  const AudioVector& Channel(size_t n) { return *channels_[n]; }
+  const AudioVector& Channel(size_t n) const { return *channels_[n]; }
+  AudioVector& Channel(size_t n) { return *channels_[n]; }
 
   // Accessors and mutators.
   size_t next_index() const { return next_index_; }