LibWeb: Add facilities to serialize EnvironmentSettingsObjects

This will be used to transfer information about the parent context to
DedicatedWorkers and future out-of-process Worker/Worklet
implementations for fetching purposes. In order to properly check
same-origin and other policies, we need to know more about the outside
settings than we were previously passing to the WebWorker process.

Userland/Libraries/LibWeb/HTML/Scripting/SerializedEnvironmentSettingsObject.cpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2024, Andrew Kaster <akaster@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibIPC/Decoder.h>
+#include <LibIPC/Encoder.h>
+#include <LibWeb/HTML/Scripting/SerializedEnvironmentSettingsObject.h>
+
+namespace IPC {
+
+template<>
+ErrorOr<void> encode(Encoder& encoder, Web::HTML::SerializedEnvironmentSettingsObject const& object)
+{
+    TRY(encoder.encode(object.id));
+    TRY(encoder.encode(object.creation_url));
+    TRY(encoder.encode(object.top_level_creation_url));
+    TRY(encoder.encode(object.top_level_origin));
+    TRY(encoder.encode(object.api_url_character_encoding));
+    TRY(encoder.encode(object.api_base_url));
+    TRY(encoder.encode(object.origin));
+    TRY(encoder.encode(object.policy_container));
+    TRY(encoder.encode(object.cross_origin_isolated_capability));
+
+    return {};
+}
+
+template<>
+ErrorOr<Web::HTML::SerializedEnvironmentSettingsObject> decode(Decoder& decoder)
+{
+    Web::HTML::SerializedEnvironmentSettingsObject object {};
+
+    object.id = TRY(decoder.decode<String>());
+    object.creation_url = TRY(decoder.decode<URL>());
+    object.top_level_creation_url = TRY(decoder.decode<URL>());
+    object.top_level_origin = TRY(decoder.decode<Web::HTML::Origin>());
+    object.api_url_character_encoding = TRY(decoder.decode<String>());
+    object.api_base_url = TRY(decoder.decode<URL>());
+    object.origin = TRY(decoder.decode<Web::HTML::Origin>());
+    object.policy_container = TRY(decoder.decode<Web::HTML::PolicyContainer>());
+    object.cross_origin_isolated_capability = TRY(decoder.decode<Web::HTML::CanUseCrossOriginIsolatedAPIs>());
+
+    return object;
+}
+
+}