Move MouseHelper.test into browser

src/browser/TestUtils.test.ts

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) 2019 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { IEvent, EventEmitter2 } from 'common/EventEmitter2';
+import { ICharSizeService } from 'browser/services/Services';
+
+export class MockCharSizeService implements ICharSizeService {
+  get hasValidSize(): boolean { return this.width > 0 && this.height > 0; }
+  onCharSizeChange: IEvent<void> = new EventEmitter2<void>().event;
+  constructor(public width: number, public height: number) {}
+  measure(): void {}
+}