fix: When disconnecting from chromecast, subtitles are turned off (#6103

)

Fixes #4036

lib/cast/cast_proxy.js

@@ -496,6 +496,16 @@ shaka.cast.CastProxy = class extends shaka.util.FakeEventTarget {
       startTime = this.sender_.get('video', 'currentTime');
     }
 
+    let activeTextTrack;
+    const textTracks = this.sender_.get('player', 'getTextTracks')();
+
+    if (textTracks && textTracks.length) {
+      activeTextTrack = textTracks.find((t) => t.active);
+    }
+
+    const isTextTrackVisible =
+        this.sender_.get('player', 'isTextTrackVisible')();
+
     // Now load the manifest, if present.
     if (assetUri) {
       // Don't autoplay the content until we finish setting up initial state.
@@ -527,6 +537,14 @@ shaka.cast.CastProxy = class extends shaka.util.FakeEventTarget {
         /** @type {Object} */(this.localPlayer_)[setter](value);
       }
 
+      this.localPlayer_.setTextTrackVisibility(isTextTrackVisible);
+      if (activeTextTrack) {
+        this.localPlayer_.selectTextLanguage(
+            activeTextTrack.language,
+            activeTextTrack.roles,
+            activeTextTrack.forced);
+      }
+
       // Restore the original autoplay setting.
       this.localVideo_.autoplay = autoplay;
       if (assetUri) {