Change a ContentInitializer dispose method to stop

This was done as it makes more sense to have an "idle" state after
stopping than disposing (in the latter case, we would have to add
something like the "disposed" state) and as it may be more portable to
allow re-using a ContentInitializer later, which however for now hasn't
any real case.

src/main_thread/api/public_api.ts

@@ -1106,7 +1106,7 @@ class Player extends EventEmitter<IPublicAPIEvent> {
       currentContentCanceller.signal,
     );
     currentContentCanceller.signal.register(() => {
-      initializer.dispose();
+      initializer.stop();
     });
 
     /**

src/main_thread/init/directfile_content_initializer.ts

@@ -212,8 +212,9 @@ export default class DirectFileContentInitializer extends ContentInitializer {
   /**
    * Stop content and free all resources linked to this `ContentIntializer`.
    */
-  public dispose(): void {
+  public stop(): void {
     this._initCanceller.cancel();
+    this._initCanceller = new TaskCanceller();
     this.state = ContentInitializerState.Idle;
     this.trigger("stateChange", this.state);
   }

src/main_thread/init/media_source_content_initializer.ts

@@ -295,12 +295,13 @@ export default class MediaSourceContentInitializer extends ContentInitializer {
    * Stop content and free all resources linked to this
    * `MediaSourceContentInitializer`.
    */
-  public dispose(): void {
+  public stop(): void {
     if (this._contentMetadata?.type === "preparing") {
       this._contentMetadata.reject(new Error("The content has been disposed"));
     }
     this._contentMetadata = null;
     this._initCanceller.cancel();
+    this._initCanceller = new TaskCanceller();
     this.state = ContentInitializerState.Idle;
     this.trigger("stateChange", this.state);
   }

src/main_thread/init/multi_thread_content_initializer.ts

@@ -1109,8 +1109,9 @@ export default class MultiThreadContentInitializer extends ContentInitializer {
     });
   }
 
-  public dispose(): void {
+  public stop(): void {
     this._initCanceller.cancel();
+    this._initCanceller = new TaskCanceller();
     if (this._currentContentInfo !== null) {
       this._currentContentInfo.mainThreadMediaSource?.dispose();
       this._currentContentInfo = null;

src/main_thread/init/types.ts

@@ -108,10 +108,12 @@ export abstract class ContentInitializer extends EventEmitter<IContentInitialize
 
   /**
    * Stop playing the content linked to this `ContentInitializer` on the
-   * `HTMLMediaElement` linked to it and dispose of every resources taken while
+   * `HTMLMediaElement` linked to it and free every resources taken while
    * trying to do so.
+   *
+   * The content could be then restarted through a `start` call.
    */
-  public abstract dispose(): void;
+  public abstract stop(): void;
 }
 
 /** List of "states" in which a `ContentInitializer` may be in. */