src/vs/workbench/api/common/extHostWindow.ts/ExtHostWindow/$onDidChangeWindowFocus
class ExtHostWindow:	$onDidChangeWindowFocus(focused: boolean): void {
		if (focused === this._state.focused) {
			return;
		}

		this._state = { ...this._state, focused };
		this._onDidChangeWindowState.fire(this._state);
	}