make perf util loadable from web, https://github.com/microsoft/vscode/issues/101850

src/vs/base/common/performance.js

@@ -73,7 +73,8 @@ function _factory(sharedObj) {
 // Because we want both instances to use the same perf-data
 // we store them globally
 
-let sharedObj;
+// eslint-disable-next-line no-var
+var sharedObj;
 if (typeof global === 'object') {
 	// nodejs
 	sharedObj = global;
@@ -91,5 +92,5 @@ if (typeof define === 'function') {
 	// commonjs
 	module.exports = _factory(sharedObj);
 } else {
-	// invalid context...
+	sharedObj.perf = _factory(sharedObj);
 }

src/vs/code/browser/workbench/workbench-dev.html

@@ -42,9 +42,13 @@
 			}
 		};
 	</script>
+	<script src="./static/out/vs/base/common/performance.js"></script>
 	<script src="./static/out/vs/loader.js"></script>
 	<script>
 		// NOTE: Changes to inline scripts require update of content security policy
-		require(['vs/code/browser/workbench/workbench'], function() {});
+		perf.mark('willLoadWorkbenchMain');
+		require(['vs/code/browser/workbench/workbench'], function() {
+			perf.mark('didLoadWorkbenchMain');
+		});
 	</script>
 </html>