Correctly dispose of Renderer and ScreenDprMonitor

src/utils/ScreenDprMonitor.ts

@@ -3,6 +3,8 @@
  * @license MIT
  */
 
+import { Disposable } from '../common/Lifecycle';
+
 export type ScreenDprListener = (newDevicePixelRatio?: number, oldDevicePixelRatio?: number) => void;
 
 /**
@@ -15,7 +17,7 @@ export type ScreenDprListener = (newDevicePixelRatio?: number, oldDevicePixelRat
  * The listener should fire on both window zoom changes and switching to a
  * monitor with a different DPI.
  */
-export class ScreenDprMonitor {
+export class ScreenDprMonitor extends Disposable {
   private _currentDevicePixelRatio: number;
   private _outerListener: MediaQueryListListener;
   private _listener: ScreenDprListener;
@@ -33,6 +35,11 @@ export class ScreenDprMonitor {
     this._updateDpr();
   }
 
+  public dispose(): void {
+    super.dispose();
+    this.clearListener();
+  }
+
   private _updateDpr(): void {
     // Clear listeners for old DPR
     if (this._resolutionMediaMatchList) {

src/utils/TestUtils.test.ts

@@ -315,6 +315,9 @@ export class MockBuffer implements IBuffer {
 }
 
 export class MockRenderer implements IRenderer {
+  dispose(): void {
+    throw new Error('Method not implemented.');
+  }
   colorManager: IColorManager;
   on(type: string, listener: XtermListener): void {
     throw new Error('Method not implemented.');