Add PeerConnectionInterface::UpdateCallBitrate.

webrtc/api/peerconnectioninterface.h

Index: webrtc/api/peerconnectioninterface.h
diff --git a/webrtc/api/peerconnectioninterface.h b/webrtc/api/peerconnectioninterface.h
index 8c5a64bf1ebf69d197ac61d55c1731e95bdf7699..8bfd4d28284db2c0339362bb868e2929664103cf 100644
--- a/webrtc/api/peerconnectioninterface.h
+++ b/webrtc/api/peerconnectioninterface.h
@@ -729,6 +729,21 @@ class PeerConnectionInterface : public rtc::RefCountInterface {
   // destroyed, RegisterUMAOberver(nullptr) should be called.
   virtual void RegisterUMAObserver(UMAObserver* observer) = 0;
 
+  // 0 <= min <= current <= max should hold for set parameters.

[kwiberg-webrtc, 2017/05/24 08:27:55]

Are all 8 combinations of set/unset supported?

[Zach Stein, 2017/05/24 21:10:02]

Yes.

+  struct BitrateParameters {
+    rtc::Optional<int> min_bitrate_bps;
+    rtc::Optional<int> current_bitrate_bps;
+    rtc::Optional<int> max_bitrate_bps;
+  };
+
+  // SetBitrate limits the bandwidth allocated for all RTP streams sent by
+  // this PeerConnection. Other limitations might affect these limits and
+  // are respected (for example "b=AS" in SDP).
+  //
+  // Changing |current_bitrate_bps| to a new value will reset the current

[Taylor Brandstetter, 2017/05/25 15:33:52]

This comment may need to be updated. It's not just changing to a new value that
will reset the current estimate, passing in *any* value will do this.

[Zach Stein, 2017/05/25 20:26:31]

Done.

+  // bitrate estimate to the provided value.
+  virtual RTCError SetBitrate(const BitrateParameters& bitrate) = 0;
+
   // Returns the current SignalingState.
   virtual SignalingState signaling_state() = 0;
   virtual IceConnectionState ice_connection_state() = 0;