Replace EventEmitter usage in CharMeasure

src/Terminal.ts

@@ -748,7 +748,7 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
     // dprchange should handle this case, we need this as well for browsers that don't support the
     // matchMedia query.
     this.register(addDisposableDomListener(window, 'resize', () => this.renderer.onWindowResize(window.devicePixelRatio)));
-    this.register(this.charMeasure.addDisposableListener('charsizechanged', () => this.renderer.onCharSizeChanged()));
+    this.register(this.charMeasure.onCharSizeChanged(() => this.renderer.onCharSizeChanged()));
     this.register(this.renderer.addDisposableListener('resize', (dimensions) => this.viewport.syncScrollArea()));
 
     this.selectionManager = new SelectionManager(this, this.charMeasure);

src/Types.ts

@@ -253,6 +253,9 @@ export interface IMouseHelper {
 export interface ICharMeasure {
   width: number;
   height: number;
+
+  onCharSizeChanged: IEvent<void>;
+
   measure(options: ITerminalOptions): void;
 }
 

src/ui/CharMeasure.ts

@@ -4,22 +4,24 @@
  */
 
 import { ICharMeasure, ITerminalOptions } from '../Types';
-import { EventEmitter } from '../common/EventEmitter';
+import { EventEmitter2, IEvent } from '../../lib/common/EventEmitter2';
 
 /**
  * Utility class that measures the size of a character. Measurements are done in
  * the DOM rather than with a canvas context because support for extracting the
  * height of characters is patchy across browsers.
  */
-export class CharMeasure extends EventEmitter implements ICharMeasure {
+export class CharMeasure implements ICharMeasure {
   private _document: Document;
   private _parentElement: HTMLElement;
   private _measureElement: HTMLElement;
   private _width: number;
   private _height: number;
 
+  private _onCharSizeChanged = new EventEmitter2<void>();
+  public get onCharSizeChanged(): IEvent<void> { return this._onCharSizeChanged.event; }
+
   constructor(document: Document, parentElement: HTMLElement) {
-    super();
     this._document = document;
     this._parentElement = parentElement;
     this._measureElement = this._document.createElement('span');
@@ -50,7 +52,7 @@ export class CharMeasure extends EventEmitter implements ICharMeasure {
     if (this._width !== geometry.width || this._height !== adjustedHeight) {
       this._width = geometry.width;
       this._height = adjustedHeight;
-      this.emit('charsizechanged');
+      this._onCharSizeChanged.fire();
     }
   }
 }

src/ui/TestUtils.test.ts

@@ -174,6 +174,7 @@ export class MockTerminal implements ITerminal {
 }
 
 export class MockCharMeasure implements ICharMeasure {
+  onCharSizeChanged: IEvent<void>;
   width: number;
   height: number;
   measure(options: ITerminalOptions): void {