[RN] Remove denied permission alert from WelcomePage

react/features/base/tracks/actions.js

                 },
                 /* firePermissionPromptIsShownEvent */ false,
                 store)
-            .then(localTracks => dispatch(_updateLocalTracks(localTracks)))
-            .catch(({ gum }) => {
-                // If permissions are not allowed, alert the user.
-                if (gum
-                        && gum.error
-                        && gum.error.name === 'DOMException'
-                        && gum.error.message === 'NotAllowedError') {
-                    dispatch({
-                        type: TRACK_PERMISSION_ERROR,
-                        trackType: device
-                    });
-                }
-            });
+            .then(
+                localTracks => dispatch(_updateLocalTracks(localTracks)),
+                reason =>
+                    dispatch(_onCreateLocalTracksRejected(reason, device)));
         }
     };
 }
     };
 }
 
+/**
+ * Implements the <tt>Promise</tt> rejection handler of
+ * <tt>createLocalTracksA</tt> and <tt>createLocalTracksF</tt>.
+ *
+ * @param {Object} reason - The <tt>Promise</tt> rejection reason.
+ * @param {string} device - The device/<tt>MEDIA_TYPE</tt> associated with the
+ * rejection.
+ * @private
+ * @returns {Function}
+ */
+function _onCreateLocalTracksRejected({ gum }, device) {
+    return dispatch => {
+        // If permissions are not allowed, alert the user.
+        if (gum) {
+            const { error } = gum;
+
+            if (error) {
+                // FIXME For whatever reason (which is probably an
+                // implementation fault), react-native-webrtc will give the
+                // error in one of the following formats depending on whether it
+                // is attached to a remote debugger or not. (The remote debugger
+                // scenario suggests that react-native-webrtc is at fault
+                // because the remote debugger is Google Chrome and then its
+                // JavaScript engine will define DOMException. I suspect I wrote
+                // react-native-webrtc to return the error in the alternative
+                // format if DOMException is not defined.)
+                let trackPermissionError;
+
+                switch (error.name) {
+                case 'DOMException':
+                    trackPermissionError = error.message === 'NotAllowedError';
+                    break;
+
+                case 'NotAllowedError':
+                    trackPermissionError = error instanceof DOMException;
+                    break;
+                }
+                trackPermissionError && dispatch({
+                    type: TRACK_PERMISSION_ERROR,
+                    trackType: device
+                });
+            }
+        }
+    };
+}
+
 /**
  * Returns true if the provided JitsiTrack should be rendered as a mirror.
  *

react/features/mobile/permissions/functions.js

-import { Alert, Linking, NativeModules } from 'react-native';
-
-import { Platform } from '../../base/react';
-
-/**
- * Shows an alert panel which tells the user they have to manually grant some
- * permissions by opening Settings. A button which opens Settings is provided.
- *
- * FIXME: translate.
- *
- * @param {string} trackType - Type of track that failed with a permission
- * error.
- * @returns {void}
- */
-export function alertPermissionErrorWithSettings(trackType) {
-    const type = trackType === 'video' ? 'Camera' : 'Microphone';
-
-    Alert.alert(
-        'Permissions Error',
-        `${type} permission is required, please enable it in Settings.`,
-        [
-            { text: 'Cancel' },
-            {
-                onPress: _openSettings,
-                text: 'Settings'
-            }
-        ],
-        { cancelable: false });
-}
-
-/**
- * Opens the settings panel for the current platform.
- *
- * @private
- * @returns {void}
- */
-function _openSettings() {
-    switch (Platform.OS) {
-    case 'android':
-        NativeModules.AndroidSettings.open();
-        break;
-
-    case 'ios':
-        Linking.openURL('app-settings:');
-        break;
-    }
-}

react/features/mobile/permissions/middleware.js

 /* @flow */
 
+import { Alert, Linking, NativeModules } from 'react-native';
+
+import { isRoomValid } from '../../base/conference';
+import { Platform } from '../../base/react';
 import { MiddlewareRegistry } from '../../base/redux';
 import { TRACK_PERMISSION_ERROR } from '../../base/tracks';
 
-import { alertPermissionErrorWithSettings } from './functions';
-
 /**
  * Middleware that captures track permission errors and alerts the user so they
  * can enable the permission themselves.
  * @param {Store} store - The redux store.
  * @returns {Function}
  */
-MiddlewareRegistry.register(() => next => action => {
+MiddlewareRegistry.register(store => next => action => {
     const result = next(action);
 
     switch (action.type) {
     case TRACK_PERMISSION_ERROR:
-        alertPermissionErrorWithSettings(action.trackType);
+        // XXX We do not currently have user interface outside of a conference
+        // which the user may tap and cause a permission-related error. If we
+        // alert whenever we (intend to) ask for a permission, the scenario of
+        // entering the WelcomePage, being asked for the camera permission, me
+        // denying it, and being alerted that there is an error is overwhelming
+        // me.
+        if (isRoomValid(store.getState()['features/base/conference'].room)) {
+            _alertPermissionErrorWithSettings(action.trackType);
+        }
         break;
     }
 
     return result;
 });
+
+/**
+ * Shows an alert panel which tells the user they have to manually grant some
+ * permissions by opening Settings. A button which opens Settings is provided.
+ *
+ * @param {string} trackType - Type of track that failed with a permission
+ * error.
+ * @private
+ * @returns {void}
+ */
+function _alertPermissionErrorWithSettings(trackType) {
+    // TODO i18n
+    const deviceType = trackType === 'video' ? 'Camera' : 'Microphone';
+
+    Alert.alert(
+        'Permission required',
+        `${deviceType
+            } permission is required to participate in conferences with ${
+            trackType}. Please grant it in Settings.`,
+        [
+            { text: 'Cancel' },
+            {
+                onPress: _openSettings,
+                text: 'Settings'
+            }
+        ],
+        { cancelable: false });
+}
+
+/**
+ * Opens the settings panel for the current platform.
+ *
+ * @private
+ * @returns {void}
+ */
+function _openSettings() {
+    switch (Platform.OS) {
+    case 'android':
+        NativeModules.AndroidSettings.open();
+        break;
+
+    case 'ios':
+        Linking.openURL('app-settings:');
+        break;
+    }
+}