chore(Demo): Add extra chapter functionality (#5796)

Related to #3597

demo/common/asset.js

@@ -45,6 +45,8 @@ const ShakaDemoAssetInfo = class {
     this.extraText = [];
     /** @type {!Array.<string>} */
     this.extraThumbnail = [];
+    /** @type {!Array.<!shakaAssets.ExtraChapter>} */
+    this.extraChapter = [];
     /** @type {?string} */
     this.certificateUri = null;
     /** @type {?string} */
@@ -321,7 +323,6 @@ const ShakaDemoAssetInfo = class {
    * @return {!ShakaDemoAssetInfo}
    */
   addExtraText(extraText) {
-    // TODO: At no point do we actually use the extraText... why does it exist?
     this.extraText.push(extraText);
     return this;
   }
@@ -335,6 +336,15 @@ const ShakaDemoAssetInfo = class {
     return this;
   }
 
+  /**
+   * @param {shakaAssets.ExtraChapter} extraChapter
+   * @return {!ShakaDemoAssetInfo}
+   */
+  addExtraChapter(extraChapter) {
+    this.extraChapter.push(extraChapter);
+    return this;
+  }
+
   /**
    * If this is called, the asset will be focused on by the integration tests.
    * @return {!ShakaDemoAssetInfo}

demo/common/assets.js

@@ -178,6 +178,23 @@ shakaAssets.Feature = {
  *   (optional) The codecs string, if needed to refine the MIME type.
  */
 shakaAssets.ExtraText;
+
+
+/**
+ * @typedef {{
+ *   uri: string,
+ *   language: string,
+ *   mime: string
+ * }}
+ *
+ * @property {string} uri
+ *   The URI of the chapter.
+ * @property {string} language
+ *   The language of the chapter (e.g. 'en').
+ * @property {string} mime
+ *   The MIME type of the chapter (e.g. 'text/vtt')
+ */
+shakaAssets.ExtraChapter;
 // End types and enums }}}
 
 

demo/main.js

@@ -1268,6 +1268,11 @@ shakaDemo.Main = class {
         this.player_.addThumbnailsTrack(extraThumbnail);
       }
 
+      for (const extraChapter of asset.extraChapter) {
+        this.player_.addChaptersTrack(extraChapter.uri, extraChapter.language,
+            extraChapter.mime);
+      }
+
       // If the asset has an ad tag attached to it, load the ads
       const adManager = this.player_.getAdManager();
       if (adManager && asset.adTagUri) {