fix(tracks): allow forcing native text tracks on or off (#4172)

In addition, the track buttons need to update on the ready event because when the tech loads, it could run with support native captions, so, it needs to know whether to include the captions settings menu.
And all tracks should always be included in player.textTracks() and not just player.remoteTextTracks().

src/js/control-bar/track-button.js

@@ -38,6 +38,7 @@ class TrackButton extends MenuButton {
 
     tracks.addEventListener('removetrack', updateHandler);
     tracks.addEventListener('addtrack', updateHandler);
+    this.player_.on('ready', updateHandler);
 
     this.player_.on('dispose', function() {
       tracks.removeEventListener('removetrack', updateHandler);

src/js/tech/html5.js

@@ -68,6 +68,7 @@ class Html5 extends Tech {
             // store HTMLTrackElement and TextTrack to remote list
             this.remoteTextTrackEls().addTrackElement_(node);
             this.remoteTextTracks().addTrack(node.track);
+            this.textTracks().addTrack(node.track);
             if (!crossoriginTracks &&
                 !this.el_.hasAttribute('crossorigin') &&
                 Url.isCrossOrigin(node.src)) {

src/js/tech/tech.js

@@ -130,8 +130,10 @@ class Tech extends Component {
       }
     });
 
-    if (options.nativeCaptions === false) {
+    if (options.nativeCaptions === false || options.nativeTextTracks === false) {
       this.featuresNativeTextTracks = false;
+    } else if (options.nativeCaptions === true || options.nativeTextTracks === true) {
+      this.featuresNativeTextTracks = true;
     }
 
     if (!this.featuresNativeTextTracks) {