Ladybird: Move Qt-specific classes and functions to a Qt subdirectory

This will help a lot with developing chromes for different UI frameworks
where we can see which helper classes and processes are really using Qt
vs just using it to get at helper data.

As a bonus, remove Qt dependency from WebDriver.

Ladybird/Qt/RequestManagerQt.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/Loader/ResourceLoader.h>
+#include <QtNetwork/QNetworkAccessManager>
+#include <QtNetwork/QNetworkReply>
+
+namespace Ladybird {
+
+class RequestManagerQt
+    : public QObject
+    , public Web::ResourceLoaderConnector {
+    Q_OBJECT
+public:
+    static NonnullRefPtr<RequestManagerQt> create()
+    {
+        return adopt_ref(*new RequestManagerQt());
+    }
+
+    virtual ~RequestManagerQt() override { }
+
+    virtual void prefetch_dns(AK::URL const&) override { }
+    virtual void preconnect(AK::URL const&) override { }
+
+    virtual RefPtr<Web::ResourceLoaderConnectorRequest> start_request(DeprecatedString const& method, AK::URL const&, HashMap<DeprecatedString, DeprecatedString> const& request_headers, ReadonlyBytes request_body, Core::ProxyData const&) override;
+
+private slots:
+    void reply_finished(QNetworkReply*);
+
+private:
+    RequestManagerQt();
+
+    class Request
+        : public Web::ResourceLoaderConnectorRequest {
+    public:
+        static ErrorOr<NonnullRefPtr<Request>> create(QNetworkAccessManager& qnam, DeprecatedString const& method, AK::URL const& url, HashMap<DeprecatedString, DeprecatedString> const& request_headers, ReadonlyBytes request_body, Core::ProxyData const&);
+
+        virtual ~Request() override;
+
+        virtual void set_should_buffer_all_input(bool) override { }
+        virtual bool stop() override { return false; }
+        virtual void stream_into(Stream&) override { }
+
+        void did_finish();
+
+        QNetworkReply& reply() { return m_reply; }
+
+    private:
+        Request(QNetworkReply&);
+
+        QNetworkReply& m_reply;
+    };
+
+    HashMap<QNetworkReply*, NonnullRefPtr<Request>> m_pending;
+    QNetworkAccessManager* m_qnam { nullptr };
+};
+
+}