Convert most top hitting eager event creations to use getters

For microsoft#262772

This covers most of the top hitters I see using the script in microsoft#262772. This script identifies cases where an event function is created but on one actually listens to it. I found these by starting up the editor and doing some basic interaction

Author: mjbvz

src/vs/base/browser/ui/dropdown/dropdownActionViewItem.ts

@@ -47,7 +47,7 @@ export class DropdownMenuActionViewItem extends BaseActionViewItem {
 	private actionItem: HTMLElement | null = null;
 
 	private _onDidChangeVisibility = this._register(new Emitter<boolean>());
-	readonly onDidChangeVisibility = this._onDidChangeVisibility.event;
+	get onDidChangeVisibility() { return this._onDidChangeVisibility.event; }
 
 	protected override readonly options: IDropdownMenuActionViewItemOptions;
 

src/vs/base/browser/ui/findinput/findInput.ts

@@ -63,25 +63,25 @@ export class FindInput extends Widget {
 	public readonly inputBox: HistoryInputBox;
 
 	private readonly _onDidOptionChange = this._register(new Emitter<boolean>());
-	public readonly onDidOptionChange: Event<boolean /* via keyboard */> = this._onDidOptionChange.event;
+	public get onDidOptionChange(): Event<boolean /* via keyboard */> { return this._onDidOptionChange.event; }
 
 	private readonly _onKeyDown = this._register(new Emitter<IKeyboardEvent>());
-	public readonly onKeyDown: Event<IKeyboardEvent> = this._onKeyDown.event;
+	public get onKeyDown(): Event<IKeyboardEvent> { return this._onKeyDown.event; }
 
 	private readonly _onMouseDown = this._register(new Emitter<IMouseEvent>());
-	public readonly onMouseDown: Event<IMouseEvent> = this._onMouseDown.event;
+	public get onMouseDown(): Event<IMouseEvent> { return this._onMouseDown.event; }
 
 	private readonly _onInput = this._register(new Emitter<void>());
-	public readonly onInput: Event<void> = this._onInput.event;
+	public get onInput(): Event<void> { return this._onInput.event; }
 
 	private readonly _onKeyUp = this._register(new Emitter<IKeyboardEvent>());
-	public readonly onKeyUp: Event<IKeyboardEvent> = this._onKeyUp.event;
+	public get onKeyUp(): Event<IKeyboardEvent> { return this._onKeyUp.event; }
 
 	private _onCaseSensitiveKeyDown = this._register(new Emitter<IKeyboardEvent>());
-	public readonly onCaseSensitiveKeyDown: Event<IKeyboardEvent> = this._onCaseSensitiveKeyDown.event;
+	public get onCaseSensitiveKeyDown(): Event<IKeyboardEvent> { return this._onCaseSensitiveKeyDown.event; }
 
 	private _onRegexKeyDown = this._register(new Emitter<IKeyboardEvent>());
-	public readonly onRegexKeyDown: Event<IKeyboardEvent> = this._onRegexKeyDown.event;
+	public get onRegexKeyDown(): Event<IKeyboardEvent> { return this._onRegexKeyDown.event; }
 
 	constructor(parent: HTMLElement | null, contextViewProvider: IContextViewProvider | undefined, options: IFindInputOptions) {
 		super();

src/vs/base/browser/ui/findinput/replaceInput.ts

@@ -70,22 +70,22 @@ export class ReplaceInput extends Widget {
 	public inputBox: HistoryInputBox;
 
 	private readonly _onDidOptionChange = this._register(new Emitter<boolean>());
-	public readonly onDidOptionChange: Event<boolean /* via keyboard */> = this._onDidOptionChange.event;
+	public get onDidOptionChange(): Event<boolean /* via keyboard */> { return this._onDidOptionChange.event; }
 
 	private readonly _onKeyDown = this._register(new Emitter<IKeyboardEvent>());
-	public readonly onKeyDown: Event<IKeyboardEvent> = this._onKeyDown.event;
+	public get onKeyDown(): Event<IKeyboardEvent> { return this._onKeyDown.event; }
 
 	private readonly _onMouseDown = this._register(new Emitter<IMouseEvent>());
-	public readonly onMouseDown: Event<IMouseEvent> = this._onMouseDown.event;
+	public get onMouseDown(): Event<IMouseEvent> { return this._onMouseDown.event; }
 
 	private readonly _onInput = this._register(new Emitter<void>());
-	public readonly onInput: Event<void> = this._onInput.event;
+	public get onInput(): Event<void> { return this._onInput.event; }
 
 	private readonly _onKeyUp = this._register(new Emitter<IKeyboardEvent>());
-	public readonly onKeyUp: Event<IKeyboardEvent> = this._onKeyUp.event;
+	public get onKeyUp(): Event<IKeyboardEvent> { return this._onKeyUp.event; }
 
 	private _onPreserveCaseKeyDown = this._register(new Emitter<IKeyboardEvent>());
-	public readonly onPreserveCaseKeyDown: Event<IKeyboardEvent> = this._onPreserveCaseKeyDown.event;
+	public get onPreserveCaseKeyDown(): Event<IKeyboardEvent> { return this._onPreserveCaseKeyDown.event; }
 
 	constructor(parent: HTMLElement | null, contextViewProvider: IContextViewProvider | undefined, private readonly _showOptionButtons: boolean, options: IReplaceInputOptions) {
 		super();

src/vs/base/browser/ui/inputbox/inputBox.ts

@@ -117,10 +117,10 @@ export class InputBox extends Widget {
 	private readonly hover: MutableDisposable<IDisposable> = this._register(new MutableDisposable());
 
 	private _onDidChange = this._register(new Emitter<string>());
-	public readonly onDidChange: Event<string> = this._onDidChange.event;
+	public get onDidChange(): Event<string> { return this._onDidChange.event; }
 
 	private _onDidHeightChange = this._register(new Emitter<number>());
-	public readonly onDidHeightChange: Event<number> = this._onDidHeightChange.event;
+	public get onDidHeightChange(): Event<number> { return this._onDidHeightChange.event; }
 
 	constructor(container: HTMLElement, contextViewProvider: IContextViewProvider | undefined, options: IInputOptions) {
 		super();

src/vs/base/browser/ui/list/listWidget.ts

@@ -120,7 +120,7 @@ class Trait<T> implements ISpliceable<boolean>, IDisposable {
 	protected sortedIndexes: number[] = [];
 
 	private readonly _onChange = new Emitter<ITraitChangeEvent>();
-	readonly onChange: Event<ITraitChangeEvent> = this._onChange.event;
+	get onChange(): Event<ITraitChangeEvent> { return this._onChange.event; }
 
 	get name(): string { return this._trait; }
 
@@ -676,7 +676,7 @@ export class MouseController<T> implements IDisposable {
 	private readonly disposables = new DisposableStore();
 
 	private readonly _onPointer = this.disposables.add(new Emitter<IListMouseEvent<T>>());
-	readonly onPointer: Event<IListMouseEvent<T>> = this._onPointer.event;
+	get onPointer() { return this._onPointer.event; }
 
 	constructor(protected list: List<T>) {
 		if (list.options.multipleSelectionSupport !== false) {

src/vs/base/browser/ui/scrollbar/scrollableElement.ts

@@ -199,10 +199,10 @@ export abstract class AbstractScrollableElement extends Widget {
 	private _inertialSpeed: { X: number; Y: number } = { X: 0, Y: 0 };
 
 	private readonly _onScroll = this._register(new Emitter<ScrollEvent>());
-	public readonly onScroll: Event<ScrollEvent> = this._onScroll.event;
+	public get onScroll(): Event<ScrollEvent> { return this._onScroll.event; }
 
 	private readonly _onWillScroll = this._register(new Emitter<ScrollEvent>());
-	public readonly onWillScroll: Event<ScrollEvent> = this._onWillScroll.event;
+	public get onWillScroll(): Event<ScrollEvent> { return this._onWillScroll.event; }
 
 	public get options(): Readonly<ScrollableElementResolvedOptions> {
 		return this._options;

src/vs/base/browser/ui/toggle/toggle.ts

@@ -122,10 +122,10 @@ export class ToggleActionViewItem extends BaseActionViewItem {
 export class Toggle extends Widget {
 
 	private readonly _onChange = this._register(new Emitter<boolean>());
-	readonly onChange: Event<boolean /* via keyboard */> = this._onChange.event;
+	get onChange(): Event<boolean /* via keyboard */> { return this._onChange.event; }
 
 	private readonly _onKeyDown = this._register(new Emitter<IKeyboardEvent>());
-	readonly onKeyDown: Event<IKeyboardEvent> = this._onKeyDown.event;
+	get onKeyDown(): Event<IKeyboardEvent> { return this._onKeyDown.event; }
 
 	private readonly _opts: IToggleOpts;
 	private _icon: ThemeIcon | undefined;

src/vs/base/browser/ui/toolbar/toolbar.ts

@@ -61,7 +61,7 @@ export class ToolBar extends Disposable {
 	private readonly element: HTMLElement;
 
 	private _onDidChangeDropdownVisibility = this._register(new EventMultiplexer<boolean>());
-	readonly onDidChangeDropdownVisibility = this._onDidChangeDropdownVisibility.event;
+	get onDidChangeDropdownVisibility() { return this._onDidChangeDropdownVisibility.event; }
 	private readonly disposables = this._register(new DisposableStore());
 
 	constructor(container: HTMLElement, contextMenuProvider: IContextMenuProvider, options: IToolBarOptions = { orientation: ActionsOrientation.HORIZONTAL }) {

src/vs/editor/common/languageFeatureRegistry.ts

@@ -59,7 +59,7 @@ export class LanguageFeatureRegistry<T> {
 	private readonly _entries: Entry<T>[] = [];
 
 	private readonly _onDidChange = new Emitter<number>();
-	readonly onDidChange = this._onDidChange.event;
+	get onDidChange() { return this._onDidChange.event; }
 
 	constructor(private readonly _notebookInfoResolver?: NotebookInfoResolver) { }
 

src/vs/editor/common/model/pieceTreeTextBuffer/pieceTreeTextBuffer.ts

@@ -39,7 +39,7 @@ export class PieceTreeTextBuffer extends Disposable implements ITextBuffer {
 	private _mightContainNonBasicASCII: boolean;
 
 	private readonly _onDidChangeContent: Emitter<void> = this._register(new Emitter<void>());
-	public readonly onDidChangeContent: Event<void> = this._onDidChangeContent.event;
+	public get onDidChangeContent(): Event<void> { return this._onDidChangeContent.event; }
 
 	constructor(chunks: StringBuffer[], BOM: string, eol: '\r\n' | '\n', containsRTL: boolean, containsUnusualLineTerminators: boolean, isBasicASCII: boolean, eolNormalized: boolean) {
 		super();