fix(settings) Disable mic/camera selection on mobile safari.

Creating a preview of the same audio/video track kills the tracks that is already being shared in the conference. Therefore, disable camera/mic selection in the settings dialog while the user is in the call. The devices are selectable from the prejoin screen settings dialog.

react/features/device-selection/components/DeviceSelection.js

      */
     disableDeviceChange: boolean,
 
+    /**
+     * Whether video input dropdown should be enabled or not.
+     */
+    disableVideoInputSelect: boolean,
+
     /**
      * Whether or not the audio permission was granted.
      */
      */
     hideAudioInputPreview: boolean,
 
+    /**
+     * If true, the button to play a test sound on the selected speaker will not be displayed.
+     * This needs to be hidden on browsers that do not support selecting an audio output device.
+     */
+    hideAudioOutputPreview: boolean,
+
     /**
      * Whether or not the audio output source selector should display. If
      * true, the audio output selector and test audio link will not be
      */
     hideVideoInputPreview: boolean,
 
-    /**
-     * Whether video output dropdown should be displayed or not.
-     * (In the case of iOS Safari)
-     */
-    hideVideoOutputSelect: boolean,
-
     /**
      * An optional callback to invoke after the component has completed its
      * mount logic.
     render() {
         const {
             hideAudioInputPreview,
-            hideAudioOutputSelect,
+            hideAudioOutputPreview,
             hideVideoInputPreview,
             selectedAudioOutputId
         } = this.props;
                         className = 'device-selectors'>
                         { this._renderSelectors() }
                     </div>
-                    { !hideAudioOutputSelect
+                    { !hideAudioOutputPreview
                         && <AudioOutputPreview
                             deviceId = { selectedAudioOutputId } /> }
                 </div>
                 devices: availableDevices.audioInput,
                 hasPermission: hasAudioPermission,
                 icon: 'icon-microphone',
-                isDisabled: this.props.disableAudioInputChange
-                    || this.props.disableDeviceChange,
+                isDisabled: this.props.disableAudioInputChange || this.props.disableDeviceChange,
                 key: 'audioInput',
                 id: 'audioInput',
                 label: 'settings.selectMic',
-                onSelect: selectedAudioInputId =>
-                    super._onChange({ selectedAudioInputId }),
+                onSelect: selectedAudioInputId => super._onChange({ selectedAudioInputId }),
                 selectedDeviceId: this.state.previewAudioTrack
-                    ? this.state.previewAudioTrack.getDeviceId() : null
-            }
-        ];
-
-        if (!this.props.hideVideoOutputSelect) {
-            configurations.unshift({
+                    ? this.state.previewAudioTrack.getDeviceId() : this.props.selectedAudioInputId
+            },
+            {
                 devices: availableDevices.videoInput,
                 hasPermission: hasVideoPermission,
                 icon: 'icon-camera',
-                isDisabled: this.props.disableDeviceChange,
+                isDisabled: this.props.disableVideoInputSelect || this.props.disableDeviceChange,
                 key: 'videoInput',
                 id: 'videoInput',
                 label: 'settings.selectCamera',
-                onSelect: selectedVideoInputId =>
-                    super._onChange({ selectedVideoInputId }),
+                onSelect: selectedVideoInputId => super._onChange({ selectedVideoInputId }),
                 selectedDeviceId: this.state.previewVideoTrack
-                    ? this.state.previewVideoTrack.getDeviceId() : null
-            });
-        }
+                    ? this.state.previewVideoTrack.getDeviceId() : this.props.selectedVideoInputId
+            }
+        ];
 
         if (!this.props.hideAudioOutputSelect) {
             configurations.push({
                 key: 'audioOutput',
                 id: 'audioOutput',
                 label: 'settings.selectAudioOutput',
-                onSelect: selectedAudioOutputId =>
-                    super._onChange({ selectedAudioOutputId }),
+                onSelect: selectedAudioOutputId => super._onChange({ selectedAudioOutputId }),
                 selectedDeviceId: this.props.selectedAudioOutputId
             });
         }

react/features/device-selection/functions.js

     const { conference } = state['features/base/conference'];
     const { permissions } = state['features/base/devices'];
     const isMobileSafari = isIosMobileBrowser();
+    const cameraChangeSupported = JitsiMeetJS.mediaDevices.isDeviceChangeAvailable('input');
+    const speakerChangeSupported = JitsiMeetJS.mediaDevices.isDeviceChangeAvailable('output');
+    const userSelectedCamera = getUserSelectedCameraDeviceId(state);
+    const userSelectedMic = getUserSelectedMicDeviceId(state);
     let disableAudioInputChange = !JitsiMeetJS.mediaDevices.isMultipleAudioInputSupported();
-    let selectedAudioInputId = settings.micDeviceId;
+    let disableVideoInputSelect = !cameraChangeSupported;
+    let selectedAudioInputId = isMobileSafari ? userSelectedMic : settings.micDeviceId;
     let selectedAudioOutputId = getAudioOutputDeviceId();
-    let selectedVideoInputId = settings.cameraDeviceId;
+    let selectedVideoInputId = isMobileSafari ? userSelectedCamera : settings.cameraDeviceId;
 
     // audio input change will be a problem only when we are in a
     // conference and this is not supported, when we open device selection on
     // on welcome page we also show only what we have saved as user selected devices
     if (!conference) {
         disableAudioInputChange = false;
-        selectedAudioInputId = getUserSelectedMicDeviceId(state);
+        disableVideoInputSelect = false;
+        selectedAudioInputId = userSelectedMic;
         selectedAudioOutputId = getUserSelectedOutputDeviceId(state);
-        selectedVideoInputId = getUserSelectedCameraDeviceId(state);
+        selectedVideoInputId = userSelectedCamera;
     }
 
     // we fill the device selection dialog with the devices that are currently
     return {
         availableDevices: state['features/base/devices'].availableDevices,
         disableAudioInputChange,
-        disableDeviceChange:
-            !JitsiMeetJS.mediaDevices.isDeviceChangeAvailable(),
+        disableDeviceChange: !JitsiMeetJS.mediaDevices.isDeviceChangeAvailable(),
+        disableVideoInputSelect,
         hasAudioPermission: permissions.audio,
         hasVideoPermission: permissions.video,
-        hideAudioInputPreview:
-            !JitsiMeetJS.isCollectingLocalStats(),
-        hideAudioOutputSelect: !JitsiMeetJS.mediaDevices
-                            .isDeviceChangeAvailable('output'),
-        hideVideoInputPreview: isMobileSafari,
-        hideVideoOutputSelect: isMobileSafari,
+        hideAudioInputPreview: disableAudioInputChange || !JitsiMeetJS.isCollectingLocalStats(),
+        hideAudioOutputPreview: !speakerChangeSupported,
+        hideAudioOutputSelect: !speakerChangeSupported,
+        hideVideoInputPreview: !cameraChangeSupported,
         selectedAudioInputId,
         selectedAudioOutputId,
         selectedVideoInputId