fix(FEC-10427): remove cues for native external subtitles (#495)

* fix(FEC-10427): remove cues from external track

Issue: safari keeps the cues from extarnal text tracks that was active and keeps playing it on the next media.
Solution: remove the cues from external text tracks.

* set prefix instead cues removal

* Update external-captions-handler.js

* Update external-captions-handler.js

* Update external-captions-handler.js

* remove cues as well

* Update external-captions-handler.js

* Update external-captions-handler.js

src/player.js

@@ -574,7 +574,8 @@ export default class Player extends FakeEventTarget {
     if (this._reset) return;
     this.pause();
     //make sure all services are reset before engine and engine attributes are reset
-    this._externalCaptionsHandler.reset();
+    // $FlowFixMe
+    this._externalCaptionsHandler.reset(this._tracks.filter(track => track.external));
     this._posterManager.reset();
     this._stateManager.reset();
     this._config.sources = {};

src/track/external-captions-handler.js

@@ -232,11 +232,13 @@ class ExternalCaptionsHandler extends FakeEventTarget {
 
   /**
    * resets the handler
+   * @param {Array<TextTrack>} externalTracks - external tracks
    * @returns {void}
    */
-  reset(): void {
+  reset(externalTracks: Array<TextTrack>): void {
     this._resetCurrentTrack();
     this._textTrackModel = {};
+    this._resetExternalNativeTextTrack(externalTracks);
     this._eventManager.removeAll();
   }
 
@@ -456,6 +458,23 @@ class ExternalCaptionsHandler extends FakeEventTarget {
     return false;
   }
 
+  /**
+   * delete cues on reset to avoid usage of the text track on the next media
+   * @param {Array<TextTrack>} externalTracks - external tracks
+   * @return {void}
+   */
+  _resetExternalNativeTextTrack(externalTracks: Array<TextTrack>): void {
+    const videoElement = this._player.getVideoElement();
+    if (videoElement) {
+      externalTracks.forEach(externalTrack => {
+        const track = Array.from(videoElement.textTracks).find(track => track && track.language === externalTrack.language);
+        if (track && track.cues) {
+          Object.values(track.cues).forEach(cue => track.removeCue(cue));
+        }
+      });
+    }
+  }
+
   /**
    * adding cues to an existing text element in a video tag
    * @param {TextTrack} textTrack - adding cues to an exiting text track element