getInstalledRelatedApps: Change internal url fields to URL type.

third_party/WebKit/public/platform/modules/installedapp/related_application.mojom

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module blink.mojom;
 
+import "url/mojo/url.mojom";
+
 // Represents a system application related to a particular web app.
 // See: https://www.w3.org/TR/appmanifest/#dfn-application-object
 struct RelatedApplication {
   string platform;
-  string? url;
+  url.mojom.Url? url;
   string? id;
 };