Adding cbr support for Opus

webrtc/modules/audio_coding/codecs/opus/opus_interface.c

Index: webrtc/modules/audio_coding/codecs/opus/opus_interface.c
diff --git a/webrtc/modules/audio_coding/codecs/opus/opus_interface.c b/webrtc/modules/audio_coding/codecs/opus/opus_interface.c
index 5bb3472b5a899fe3d0d2aa7b3ebbc2578b5242b8..59c6c9b2a0c0af34b2afd4387cbb47f8df568fd9 100644
--- a/webrtc/modules/audio_coding/codecs/opus/opus_interface.c
+++ b/webrtc/modules/audio_coding/codecs/opus/opus_interface.c
@@ -205,6 +205,22 @@ int16_t WebRtcOpus_DisableDtx(OpusEncInst* inst) {
   }
 }
 
+int16_t WebRtcOpus_EnableCbr(OpusEncInst* inst) {
+  if (inst) {
+    return opus_encoder_ctl(inst->encoder, OPUS_SET_VBR(0));
+  } else {
+    return -1;
+  }
+}
+
+int16_t WebRtcOpus_DisableCbr(OpusEncInst* inst) {
+  if (inst) {
+    return opus_encoder_ctl(inst->encoder, OPUS_SET_VBR(1));
+  } else {
+    return -1;
+  }
+}
+
 int16_t WebRtcOpus_SetComplexity(OpusEncInst* inst, int32_t complexity) {
   if (inst) {
     return opus_encoder_ctl(inst->encoder, OPUS_SET_COMPLEXITY(complexity));