stream attributes not being updated (and maybe more)

[serl]

Hello,
I'm experiencing some issues in erizoClient while updating from Licode v3 to the last master version.

In particular, I massively use stream attributes and I update them on the fly, so to have something persistent and get notified of the change on the remote side... but now when I call stream.updateAttributes(), the attributes go to undefined and nothing works.

Digging in erizo_controller/erizoClient/src led me to a promising track:

• The setAttribute function emits an StreamEvent, with the property attrs set to the new attributes

  licode/erizo_controller/erizoClient/src/Stream.js

  Line 61 in 435d517

  that.emit(StreamEvent({ type: 'internal-set-attributes', stream: that, attrs }));

• In Events.js, StreamEvent is set to have only stream and msg (actually, its parent LicodeEvent was transparent to extra attributes in v3, but it isn't anymore)

  licode/erizo_controller/erizoClient/src/Events.js

  Line 101 in 435d517

  const StreamEvent = (spec) => {

• So in Room.js, when trying to access the attrs property of the event, we get an undefined

  licode/erizo_controller/erizoClient/src/Room.js

  Line 334 in 435d517

  const attrs = evt.attrs;

The remote counterpart looks broken as well. Probably all the events need to be double checked for similar issues.

[serl]

I checked all events and the only property missing was attrs in StreamEvents used in this case... so I added it in the push request above.