feat(api): expose method for playing touch tones (#4584)

doc/api.md

 api.executeCommand('password', 'The Password');
 ```
 
+* **sendTones** - Play touch tones.
+```javascript
+api.executeCommand('sendTones', {
+    tones: string, // The dial pad touch tones to play. For example, '12345#'.
+    duration: number, // Optional. The number of milliseconds each tone should play. The default is 200.
+    pause: number // Optional. The number of milliseconds between each tone. The default is 200.
+});
+```
+
 * **subject** - Sets the subject of the conference. This command requires one argument - the new subject to be set.
 ```javascript
 api.executeCommand('subject', 'New Conference Subject');

modules/API/API.js

     createApiEvent,
     sendAnalytics
 } from '../../react/features/analytics';
-import { setPassword, setSubject } from '../../react/features/base/conference';
+import {
+    sendTones,
+    setPassword,
+    setSubject
+} from '../../react/features/base/conference';
 import { parseJWTFromURLParams } from '../../react/features/base/jwt';
 import { invite } from '../../react/features/invite';
 import { toggleTileView } from '../../react/features/video-layout';
         'proxy-connection-event': event => {
             APP.conference.onProxyConnectionEvent(event);
         },
+        'send-tones': (options = {}) => {
+            const { duration, tones, pause } = options;
+
+            APP.store.dispatch(sendTones(tones, duration, pause));
+        },
         'subject': subject => {
             sendAnalytics(createApiEvent('subject.changed'));
             APP.store.dispatch(setSubject(subject));

modules/API/external/external_api.js

     email: 'email',
     hangup: 'video-hangup',
     password: 'password',
+    sendTones: 'send-tones',
     subject: 'subject',
     submitFeedback: 'submit-feedback',
     toggleAudio: 'toggle-audio',

react/features/base/conference/actionTypes.js

  */
 export const P2P_STATUS_CHANGED = 'P2P_STATUS_CHANGED';
 
+/**
+ * The type of (redux) action which signals to play specified touch tones.
+ *
+ * {
+ *     type: SEND_TONES,
+ *     tones: string,
+ *     duration: number,
+ *     pause: number
+ * }
+ */
+export const SEND_TONES = 'SEND_TONES';
+
 /**
  * The type of (redux) action which sets the desktop sharing enabled flag for
  * the current conference.

react/features/base/conference/actions.js

     KICKED_OUT,
     LOCK_STATE_CHANGED,
     P2P_STATUS_CHANGED,
+    SEND_TONES,
     SET_DESKTOP_SHARING_ENABLED,
     SET_FOLLOW_ME,
     SET_MAX_RECEIVER_VIDEO_QUALITY,
     };
 }
 
+/**
+ * Signals to play touch tones.
+ *
+ * @param {string} tones - The tones to play.
+ * @param {number} [duration] - How long to play each tone.
+ * @param {number} [pause] - How long to pause between each tone.
+ * @returns {{
+ *     type: SEND_TONES,
+ *     tones: string,
+ *     duration: number,
+ *     pause: number
+ * }}
+ */
+export function sendTones(tones: string, duration: number, pause: number) {
+    return {
+        type: SEND_TONES,
+        tones,
+        duration,
+        pause
+    };
+}
+
 /**
  * Sets the flag for indicating if desktop sharing is enabled.
  *

react/features/base/conference/middleware.js

     CONFERENCE_SUBJECT_CHANGED,
     CONFERENCE_WILL_LEAVE,
     DATA_CHANNEL_OPENED,
+    SEND_TONES,
     SET_PENDING_SUBJECT_CHANGE,
     SET_ROOM
 } from './actionTypes';
     case PIN_PARTICIPANT:
         return _pinParticipant(store, next, action);
 
+    case SEND_TONES:
+        return _sendTones(store, next, action);
+
     case SET_ROOM:
         return _setRoom(store, next, action);
 
     return next(action);
 }
 
+/**
+ * Requests the specified tones to be played.
+ *
+ * @param {Store} store - The redux store in which the specified {@code action}
+ * is being dispatched.
+ * @param {Dispatch} next - The redux {@code dispatch} function to dispatch the
+ * specified {@code action} to the specified {@code store}.
+ * @param {Action} action - The redux action {@code SEND_TONES} which is
+ * being dispatched in the specified {@code store}.
+ * @private
+ * @returns {Object} The value returned by {@code next(action)}.
+ */
+function _sendTones({ getState }, next, action) {
+    const state = getState();
+    const { conference } = state['features/base/conference'];
+
+    if (conference) {
+        const { duration, tones, pause } = action;
+
+        conference.sendTones(tones, duration, pause);
+    }
+
+    return next(action);
+}
+
 /**
  * Helper function for updating the preferred receiver video constraint, based
  * on the user preference and the internal maximum.