LibWeb: Implement ad-hoc steps to allow LibWeb to load resource:// URLs

The resource:// scheme is used for Core::Resource files. Currently, any
users of resource:// URLs in Ladybird must manually create the Resource
and extract its data. This will allow for passing the resource:// URL
along for LibWeb to handle.

Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp

@@ -832,6 +832,10 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<PendingResponse>> scheme_fetch(JS::Realm& r
         // Return the result of running HTTP fetch given fetchParams.
         return http_fetch(realm, fetch_params);
     }
+    // AD-HOC: "resource"
+    else if (request->current_url().scheme() == "resource"sv) {
+        return TRY(nonstandard_resource_loader_file_or_http_network_fetch(realm, fetch_params));
+    }
 
     // 4. Return a network error.
     auto message = request->current_url().scheme() == "about"sv

Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.h

@@ -27,7 +27,10 @@ inline constexpr Array HTTP_SCHEMES = {
 // https://fetch.spec.whatwg.org/#fetch-scheme
 // A fetch scheme is "about", "blob", "data", "file", or an HTTP(S) scheme.
 inline constexpr Array FETCH_SCHEMES = {
-    "about"sv, "blob"sv, "data"sv, "file"sv, "http"sv, "https"sv
+    "about"sv, "blob"sv, "data"sv, "file"sv, "http"sv, "https"sv,
+
+    // AD-HOC: Internal fetch schemes:
+    "resource"sv
 };
 
 [[nodiscard]] bool is_local_url(AK::URL const&);