Merge from vscode 8e0f348413f4f616c23a88ae30030efa85811973 (#6381)

* Merge from vscode 8e0f348413f4f616c23a88ae30030efa85811973

* disable strict null check

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

@@ -0,0 +1,36 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { MainContext, MainThreadLabelServiceShape, IExtHostContext } from 'vs/workbench/api/common/extHost.protocol';
+import { extHostNamedCustomer } from 'vs/workbench/api/common/extHostCustomers';
+import { ResourceLabelFormatter, ILabelService } from 'vs/platform/label/common/label';
+import { IDisposable, dispose } from 'vs/base/common/lifecycle';
+
+@extHostNamedCustomer(MainContext.MainThreadLabelService)
+export class MainThreadLabelService implements MainThreadLabelServiceShape {
+
+	private readonly _resourceLabelFormatters = new Map<number, IDisposable>();
+
+	constructor(
+		_: IExtHostContext,
+		@ILabelService private readonly _labelService: ILabelService
+	) { }
+
+	$registerResourceLabelFormatter(handle: number, formatter: ResourceLabelFormatter): void {
+		// Dynamicily registered formatters should have priority over those contributed via package.json
+		formatter.priority = true;
+		const disposable = this._labelService.registerFormatter(formatter);
+		this._resourceLabelFormatters.set(handle, disposable);
+	}
+
+	$unregisterResourceLabelFormatter(handle: number): void {
+		dispose(this._resourceLabelFormatters.get(handle));
+		this._resourceLabelFormatters.delete(handle);
+	}
+
+	dispose(): void {
+		// noop
+	}
+}