[webrtc-pc] maximum bandwidth: TIAS or AS?

fippo has just created a new issue for https://github.com/w3c/webrtc-pc:

== maximum bandwidth: TIAS or AS? ==
http://w3c.github.io/webrtc-pc/#dom-rtcrtpencodingparameters-maxbitrate mentions TIAS. Does that imply support for AS is not required?

Or does JSEP suggest internally processing everything as TIAS here:
```
For any specified "TIAS" bandwidth value, set this value as a constraint on the maximum RTP bitrate to be used when sending media, as specified in [RFC3890]. If a "TIAS" value is not present, but an "AS" value is specified, generate a "TIAS" value using this formula:
```
if yes this might require some wordsmithing to recognize this here.

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/1249 using your GitHub account