fix: unmute video on audio only switch off

Will unmute local video (and ask for permissions if needed) in case user
started in audio only mode and is turing it off.

conference.js

 let room;
 let connection;
 let localAudio, localVideo;
-let initialAudioMutedState = false, initialVideoMutedState = false;
+let initialAudioMutedState = false;
 
 import {VIDEO_CONTAINER_TYPE} from "./modules/UI/videolayout/VideoContainer";
 
 
                         return [];
                     });
+
+            // Enable audio only mode
+            if (config.startAudioOnly) {
+                APP.store.dispatch(toggleAudioOnly());
+            }
         } else if (options.startScreenSharing) {
             tryCreateLocalTracks = this._createDesktopTrack()
                 .then(desktopStream => {
                     });
             }).then(([tracks, con]) => {
                 tracks.forEach(track => {
-                    if((track.isAudioTrack() && initialAudioMutedState)
-                        || (track.isVideoTrack() && initialVideoMutedState)) {
+                    if (track.isAudioTrack() && initialAudioMutedState) {
+                        track.mute();
+                    } else if (track.isVideoTrack() && this.videoMuted) {
                         track.mute();
                     }
                 });
                     this.updateVideoIconEnabled();
                 }
 
-                // Enable audio only mode
-                if (config.startAudioOnly) {
-                    // It is important to have that toggled after video muted
-                    // state is adjusted by the code about lack of video tracks
-                    // above. That's because audio only will store muted state
-                    // on toggle action.
-                    APP.store.dispatch(toggleAudioOnly());
-                }
-
                 this._initDeviceList();
 
                 if (config.iAmRecorder)
     /**
      * Simulates toolbar button click for video mute. Used by shortcuts and API.
      * @param mute true for mute and false for unmute.
-     */
-    muteVideo(mute) {
-        muteLocalVideo(mute);
+     * @param {boolean} [showUI] when set to false will not display any error
+     * dialogs in case of media permissions error.
+     */
+    muteVideo(mute, showUI = true) {
+        if (!localVideo && this.videoMuted && !mute) {
+            // Try to create local video if there wasn't any.
+            // This handles the case when user joined with no video
+            // (dismissed screen sharing screen or in audio only mode), but
+            // decided to add it later on by clicking on muted video icon or
+            // turning off the audio only mode.
+            //
+            // FIXME when local track creation is moved to react/redux
+            // it should take care of the use case described above
+            createLocalTracks({ devices: ['video'] }, false)
+                .then(([videoTrack]) => videoTrack)
+                .catch(error => {
+                    // FIXME should send some feedback to the API on error ?
+                    if (showUI) {
+                        APP.UI.showDeviceErrorDialog(null, error);
+                    }
+                    // Rollback the video muted status by using null track
+                    return null;
+                })
+                .then(videoTrack => this.useVideoStream(videoTrack));
+        } else {
+            muteLocalVideo(mute);
+        }
     },
     /**
      * Simulates toolbar button click for video mute. Used by shortcuts and API.
-     * @param {boolean} force - If the track is not created, the operation
-     * will be executed after the track is created. Otherwise the operation
-     * will be ignored.
+     * @param {boolean} [showUI] when set to false will not display any error
+     * dialogs in case of media permissions error.
      */
-    toggleVideoMuted(force = false) {
-        if(!localVideo && force) {
-            initialVideoMutedState = !initialVideoMutedState;
-            return;
-        }
-        this.muteVideo(!this.videoMuted);
+    toggleVideoMuted(showUI = true) {
+        this.muteVideo(!this.videoMuted, showUI);
     },
     /**
      * Retrieve list of conference participants (without local user).
         APP.UI.addListener(UIEvents.VIDEO_MUTED, muted => {
             if (this.isAudioOnly() && !muted) {
                 this._displayAudioOnlyTooltip('videoMute');
-            } else if (!localVideo && this.videoMuted && !muted) {
-                // Maybe try to create local video if there wasn't any ?
-                // This handles the case when user joined with no video
-                // (dismissed screen sharing screen), but decided to add it
-                // later on by clicking on muted video icon.
-                createLocalTracks({ devices: ['video'] }, false)
-                    .then(([videoTrack]) => {
-                        APP.conference.useVideoStream(videoTrack);
-                    })
-                    .catch(error => {
-                        APP.UI.showDeviceErrorDialog(null, error);
-                    });
             } else {
-                muteLocalVideo(muted);
+                this.muteVideo(muted);
             }
         });
 
         );
 
         APP.UI.addListener(UIEvents.TOGGLE_AUDIO_ONLY, audioOnly => {
-            muteLocalVideo(audioOnly);
+            this.muteVideo(audioOnly);
 
             // Immediately update the UI by having remote videos and the large
             // video update themselves instead of waiting for some other event

modules/API/API.js

         'display-name':
             APP.conference.changeLocalDisplayName.bind(APP.conference),
         'toggle-audio': () => APP.conference.toggleAudioMuted(true),
-        'toggle-video': () => APP.conference.toggleVideoMuted(true),
+        'toggle-video': () => {
+            APP.conference.toggleVideoMuted(false /* no UI */);
+        },
         'toggle-film-strip': APP.UI.toggleFilmstrip,
         'toggle-chat': APP.UI.toggleChat,
         'toggle-contact-list': APP.UI.toggleContactList,