Fix marker dispose unit tests

src/browser/Terminal.test.ts

@@ -1378,7 +1378,6 @@ describe('Terminal', () => {
       assert.deepEqual(disposeStack, [markers[0], markers[1]]);
       // trimmed marker objs should be disposed
       assert.deepEqual(disposeStack.map(el => el.isDisposed), [true, true]);
-      assert.deepEqual(disposeStack.map(el => (el as any)._isDisposed), [true, true]);
       // trimmed markers should contain line -1
       assert.deepEqual(disposeStack.map(el => el.line), [-1, -1]);
     });

src/common/buffer/Marker.ts

@@ -4,27 +4,40 @@
  */
 
 import { EventEmitter } from 'common/EventEmitter';
-import { Disposable, toDisposable } from 'common/Lifecycle';
-import { IMarker } from 'common/Types';
+import { disposeArray } from 'common/Lifecycle';
+import { IDisposable, IMarker } from 'common/Types';
 
-export class Marker extends Disposable implements IMarker {
+export class Marker implements IMarker {
   private static _nextId = 1;
 
+  public isDisposed: boolean = false;
+  private _disposables: IDisposable[] = [];
+
   private _id: number = Marker._nextId++;
   public get id(): number { return this._id; }
 
-  private readonly _onDispose = this.register(new EventEmitter<void>());
-  public readonly onDispose = this._onDispose.event;
 
-  public get isDisposed(): boolean { return this._isDisposed; }
+  private readonly _onDispose = new EventEmitter<void>();
+  public readonly onDispose = this._onDispose.event;
 
   constructor(
     public line: number
   ) {
-    super();
-    this.register(toDisposable(() => {
-      this.line = -1;
-      this._onDispose.fire();
-    }));
+  }
+
+  public dispose(): void {
+    if (this.isDisposed) {
+      return;
+    }
+    this.isDisposed = true;
+    this.line = -1;
+    // Emit before super.dispose such that dispose listeners get a change to react
+    this._onDispose.fire();
+    disposeArray(this._disposables);
+  }
+
+  public register(disposable: IDisposable): void {
+    this._disposables.push(disposable);
+    this._disposables.length = 0;
   }
 }