Refactor media info handling into a controller.

src/utils/media-info-controller.ts

@@ -0,0 +1,27 @@
+import { MediaLoadedInfo } from '../types';
+
+export class MediaLoadedInfoController {
+  protected _current: MediaLoadedInfo | null = null;
+  protected _lastKnown: MediaLoadedInfo | null = null;
+
+  public set(current: MediaLoadedInfo): void {
+    this._current = current;
+    this._lastKnown = current;
+  }
+
+  public get(): MediaLoadedInfo | null {
+    return this._current;
+  }
+
+  public getLastKnown(): MediaLoadedInfo | null {
+    return this._lastKnown;
+  }
+
+  public clear(): void {
+    this._current = null;
+  }
+
+  public has(): boolean {
+    return !!this._current;
+  }
+}