Add DisposableMap helper (#163006)

Adds `DisposableMap` to help manage the lifecycle of maps of  disposable values. This is useful for a few reasons:

- `DisposableMap` is itself disposable, so you can use it with `_register` or add it to a `DisposableStore`
- The implementation of `set` on `DisposableMap` prevents leaking values on override
- The `delete` implementation also makes sure it disposes of the deleted values

src/vs/workbench/api/browser/mainThreadLanguageFeatures.ts

@@ -8,7 +8,7 @@ import { CancellationToken } from 'vs/base/common/cancellation';
 import { createStringDataTransferItem, VSDataTransfer } from 'vs/base/common/dataTransfer';
 import { CancellationError } from 'vs/base/common/errors';
 import { Emitter, Event } from 'vs/base/common/event';
-import { combinedDisposable, Disposable, IDisposable, toDisposable } from 'vs/base/common/lifecycle';
+import { combinedDisposable, Disposable, DisposableMap, toDisposable } from 'vs/base/common/lifecycle';
 import { revive } from 'vs/base/common/marshalling';
 import { mixin } from 'vs/base/common/objects';
 import { URI } from 'vs/base/common/uri';
@@ -38,7 +38,7 @@ import { ExtHostContext, ExtHostLanguageFeaturesShape, ICallHierarchyItemDto, IC
 export class MainThreadLanguageFeatures extends Disposable implements MainThreadLanguageFeaturesShape {
 
 	private readonly _proxy: ExtHostLanguageFeaturesShape;
-	private readonly _registrations = new Map<number, IDisposable>();
+	private readonly _registrations = this._register(new DisposableMap<number>());
 
 	constructor(
 		extHostContext: IExtHostContext,
@@ -80,21 +80,8 @@ export class MainThreadLanguageFeatures extends Disposable implements MainThread
 		}
 	}
 
-	override dispose(): void {
-		for (const registration of this._registrations.values()) {
-			registration.dispose();
-		}
-		this._registrations.clear();
-
-		super.dispose();
-	}
-
 	$unregister(handle: number): void {
-		const registration = this._registrations.get(handle);
-		if (registration) {
-			registration.dispose();
-			this._registrations.delete(handle);
-		}
+		this._registrations.deleteAndDispose(handle);
 	}
 
 	//#region --- revive functions