LibWeb: Abstract the LibProtocol ResourceLoader connection

This is the final component that required LibProtocol as a dependency
of LibWeb. With this, we can now remove the dependency, and LibWeb no
longer requires IPC to work :^)

Userland/Libraries/LibWebView/RequestServerAdapter.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022, Dex♪ <dexes.ttp@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Function.h>
+#include <AK/URL.h>
+#include <LibWeb/Loader/ResourceLoader.h>
+
+namespace Protocol {
+class Request;
+class RequestClient;
+}
+
+namespace WebView {
+
+class RequestServerRequestAdapter
+    : public Web::ResourceLoaderConnectorRequest
+    , public Weakable<RequestServerRequestAdapter> {
+public:
+    static ErrorOr<NonnullRefPtr<RequestServerRequestAdapter>> try_create(NonnullRefPtr<Protocol::Request>);
+    virtual ~RequestServerRequestAdapter() override;
+
+    virtual void set_should_buffer_all_input(bool) override;
+    virtual bool stop() override;
+
+    virtual void stream_into(Core::Stream::Stream&) override;
+
+private:
+    RequestServerRequestAdapter(NonnullRefPtr<Protocol::Request>);
+    NonnullRefPtr<Protocol::Request> m_request;
+};
+
+class RequestServerAdapter : public Web::ResourceLoaderConnector {
+public:
+    static ErrorOr<NonnullRefPtr<RequestServerAdapter>> try_create();
+    virtual ~RequestServerAdapter() override;
+
+    virtual void prefetch_dns(AK::URL const& url) override;
+    virtual void preconnect(AK::URL const& url) override;
+
+    virtual RefPtr<Web::ResourceLoaderConnectorRequest> start_request(String const& method, URL const&, HashMap<String, String> const& request_headers = {}, ReadonlyBytes request_body = {}, Core::ProxyData const& = {}) override;
+
+private:
+    RequestServerAdapter(NonnullRefPtr<Protocol::RequestClient> protocol_client);
+
+    RefPtr<Protocol::RequestClient> m_protocol_client;
+};
+
+}