[RN] Add ability to loop sounds

react/features/base/media/components/AbstractAudio.js

     currentTime?: number,
     pause: () => void,
     play: () => void,
-    setSinkId?: string => void
+    setSinkId?: string => void,
+    stop: () => void
 };
 
 /**
         this.setAudioElementImpl = this.setAudioElementImpl.bind(this);
     }
 
-    pause: () => void;
-
     /**
      * Attempts to pause the playback of the media.
      *
         this._audioElementImpl && this._audioElementImpl.pause();
     }
 
-    play: () => void;
-
     /**
-     * Attempts to being the playback of the media.
+     * Attempts to begin the playback of the media.
      *
      * @public
      * @returns {void}
         typeof setRef === 'function' && setRef(element ? this : null);
     }
 
-    setSinkId: string => void;
-
     /**
      * Sets the sink ID (output device ID) on the underlying audio element.
      * NOTE: Currently, implemented only on Web.
             && typeof this._audioElementImpl.setSinkId === 'function'
             && this._audioElementImpl.setSinkId(sinkId);
     }
+
+    /**
+     * Attempts to stop the playback of the media.
+     *
+     * @public
+     * @returns {void}
+     */
+    stop(): void {
+        this._audioElementImpl && this._audioElementImpl.stop();
+    }
 }

react/features/base/media/components/native/Audio.js

  * {@link RTCView}.
  */
 export default class Audio extends AbstractAudio {
-
     /**
      * Reference to 'react-native-sound} {@link Sound} instance.
      */
-    _sound: Sound
+    _sound: ?Sound;
 
     /**
      * A callback passed to the 'react-native-sound''s {@link Sound} instance,
      */
     componentWillUnmount() {
         if (this._sound) {
-            this.setAudioElementImpl(null);
             this._sound.release();
             this._sound = null;
+            this.setAudioElementImpl(null);
+        }
+    }
+
+    /**
+     * Attempts to begin the playback of the media.
+     *
+     * @inheritdoc
+     * @override
+     */
+    play() {
+        if (this._sound) {
+            this._sound.setNumberOfLoops(this.props.loop ? -1 : 0);
+            super.play();
         }
     }
 
      * @returns {void}
      */
     stop() {
-        // Currently not implemented for mobile. If needed, a possible
-        // implementation is:
-        // if (this._sound) {
-        //     this._sound.stop();
-        // }
+        if (this._sound) {
+            this._sound.stop();
+        }
     }
 }