Adding cbr support for Opus

webrtc/modules/audio_coding/codecs/audio_encoder.cc

Index: webrtc/modules/audio_coding/codecs/audio_encoder.cc
diff --git a/webrtc/modules/audio_coding/codecs/audio_encoder.cc b/webrtc/modules/audio_coding/codecs/audio_encoder.cc
index 9e0cf4a510f3b3f7f748de449a53efedfbd2c220..3ce517435b55612c1c6e5b7b04febc072ac7e9d8 100644
--- a/webrtc/modules/audio_coding/codecs/audio_encoder.cc
+++ b/webrtc/modules/audio_coding/codecs/audio_encoder.cc
@@ -54,6 +54,14 @@ bool AudioEncoder::GetDtx() const {
   return false;
 }
 
+bool AudioEncoder::SetCbr(bool enable) {
+  return !enable;
+}
+
+bool AudioEncoder::GetCbr() const {
+  return false;
+}
+
 bool AudioEncoder::SetApplication(Application application) {
   return false;
 }