From: Mike Lothian <mike@fireburn.co.uk>
Subject: [PATCH] devtools: fix typescript isolated declarations in DispatchHttpRequestClient

Explicitly type optional parameter property as undefined for isolatedDeclarations.
---
--- a/third_party/devtools-frontend/src/front_end/core/host/DispatchHttpRequestClient.ts
+++ b/third_party/devtools-frontend/src/front_end/core/host/DispatchHttpRequestClient.ts
@@ -17,3 +17,3 @@
 export class DispatchHttpRequestError extends Error {
-  constructor(readonly type: ErrorType, readonly response?: DispatchHttpRequestResult, options?: ErrorOptions) {
+  constructor(readonly type: ErrorType, readonly response?: DispatchHttpRequestResult | undefined, options?: ErrorOptions) {
     super(undefined, options);