Make joining the call synchronous

Joining a call was already partially synchronous (it waited until the
media permissions were granted and the local media started), but it did
not wait until the call was joined in the server. However, as the store
is updated with the new call flags when "joinCall" returns the store was
updated before the call was actually joined in the server.

If the call status was fetched again from the server before the call was
finally joined then the received status overwrote the one set locally.
As whether the call view is shown or not is based on the call status
this could cause the call view to be shown, then hidden, and then shown
again once the call was finally joined.

To prevent that now "joinCall" waits until the call was joined in the
server, so the local call status always matches the call status in the
server, and thus the call view is no longer shown, hidden and shown
again.

An alternative approach would have been to prefer the local call status
over the one sent by the server. However, if the call view is shown
before the call is joined in the server the call view is empty (there
will be no other participant); from a user point of view it is clearer
if joining the call shows a loading spinner in the button and takes some
time than if the call view is shown with no other participant and no
sign of joining the call still being in progress.

Also, this makes joining the call behave similar to leaving it, as
leaving the call was already synchronous.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

src/utils/webrtc/index.js

@@ -96,6 +96,7 @@ async function connectSignaling(token) {
 
 let pendingJoinCallToken = null
 let startedCall = null
+let failedToStartCall = null
 
 function startCall(signaling, configuration) {
 	let flags = PARTICIPANT.CALL_FLAG.IN_CALL
@@ -108,9 +109,11 @@ function startCall(signaling, configuration) {
 		}
 	}
 
-	signaling.joinCall(pendingJoinCallToken, flags)
-
-	startedCall()
+	signaling.joinCall(pendingJoinCallToken, flags).then(() => {
+		startedCall()
+	}).catch(error => {
+		failedToStartCall(error)
+	})
 }
 
 function setupWebRtc() {
@@ -162,6 +165,7 @@ async function signalingJoinCall(token) {
 
 		return new Promise((resolve, reject) => {
 			startedCall = resolve
+			failedToStartCall = reject
 
 			webRtc.startMedia(token)
 		})