Conclusion of RTCIceServer multiple-URI thread

Summarizing from the thread "Allowing RTCIceServer to contain multiple
URLs", here are the recommended changes to be included into the spec. I
also noted that the previous agreement on adding the |username| field has
not yet made it into the editor's draft, so it is included in the changes
below.

Current:

dictionary RTCIceServer {    DOMString  url
<http://dev.w3.org/2011/webrtc/editor/webrtc.html#widl-RTCIceServer-url>;
   DOMString? credential
<http://dev.w3.org/2011/webrtc/editor/webrtc.html#widl-RTCIceServer-credential>;
};


Proposed:

dictionary RTCIceServer {    DOMString[]  url
<http://dev.w3.org/2011/webrtc/editor/webrtc.html#widl-RTCIceServer-url>s;
 // for backwards compatibility, implementations
 // should also handle |url|   DOMString?  username
<http://dev.w3.org/2011/webrtc/editor/webrtc.html#widl-RTCIceServer-url>;
 // previously agreed upon    DOMString? credential
<http://dev.w3.org/2011/webrtc/editor/webrtc.html#widl-RTCIceServer-credential>;
};4.2.2.1 Dictionary RTCIceServer
<http://dev.w3.org/2011/webrtc/editor/webrtc.html#idl-def-RTCIceServer>
Membersusername of type DOMString, nullable

If the url element of the internal array is a TURN URI, then this is
the username to use with that TURN server.

credential of type DOMString, nullable

If the url element of the internal array is a TURN URI, then this is
the password to use with that TURN server.
urls of type DOMString[]

A list of STUN or TURN URIs as defined in [STUN-URI
<http://dev.w3.org/2011/webrtc/editor/webrtc.html#bib-STUN-URI>] and
[TURN-URI <http://dev.w3.org/2011/webrtc/editor/webrtc.html#bib-TURN-URI>].
If multiple URIs are present, they represent alternate ways to contact
the STUN/TURN server, listed in order of preference.