Improve performance of language detection (#130006)

* initial move to worker

* move event handling to the untitledTextEditorModel

* reuse simpleWorker interfaces and classes

* use correct path to languageDetection

* have vscode-languagedetection be outside of the asar

* add telemetry

* don't unpackage anything from languagedetection because it's not needed

* add an integration test

* some of Ben's feedback

* rework worker code to avoid duplication

* add isDisposed check

* fix test

* Isi and Ben feedback part 2

* use RunOnceScheduler instead and try to fix the test using events

* Ben feedback part 3

* bump distro

extensions/vscode-api-tests/src/singlefolder-tests/untitled.languagedetection.test.ts

@@ -0,0 +1,65 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as assert from 'assert';
+import * as vscode from 'vscode';
+import { asPromise, assertNoRpc, closeAllEditors } from '../utils';
+
+suite('vscode - untitled automatic language detection', () => {
+
+	teardown(async function () {
+		assertNoRpc();
+		await closeAllEditors();
+	});
+
+	test('test automatic language detection works', async () => {
+		const doc = await vscode.workspace.openTextDocument();
+		const editor = await vscode.window.showTextDocument(doc);
+
+		assert.strictEqual(editor.document.languageId, 'plaintext');
+
+		const settingResult = vscode.workspace.getConfiguration().get<boolean>('workbench.editor.untitled.experimentalLanguageDetection');
+		assert.ok(settingResult);
+
+		const result = await editor.edit(editBuilder => {
+			editBuilder.insert(new vscode.Position(0, 0), `{
+	"extends": "./tsconfig.base.json",
+	"compilerOptions": {
+		"removeComments": false,
+		"preserveConstEnums": true,
+		"sourceMap": false,
+		"outDir": "../out/vs",
+		"target": "es2020",
+		"types": [
+			"keytar",
+			"mocha",
+			"semver",
+			"sinon",
+			"winreg",
+			"trusted-types",
+			"wicg-file-system-access"
+		],
+		"plugins": [
+			{
+				"name": "tsec",
+				"exemptionConfig": "./tsec.exemptions.json"
+			}
+		]
+	},
+	"include": [
+		"./typings",
+		"./vs"
+	]
+}`);
+		});
+
+		assert.ok(result);
+
+		// Changing the language triggers a file to be closed and opened again so wait for that event to happen.
+		const newDoc = await asPromise(vscode.workspace.onDidOpenTextDocument, 5000);
+
+		assert.strictEqual(newDoc.languageId, 'json');
+	});
+});