LibGUI+Browser: Move GUI::UrlBox to the Browser application

Browser is the only user of this component. Move it to allow making use
of LibWebView for URL highlighting.

Userland/Applications/Browser/URLBox.cpp

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2023, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/URL.h>
+#include <Applications/Browser/URLBox.h>
+#include <LibGfx/Palette.h>
+#include <LibGfx/TextAttributes.h>
+
+namespace Browser {
+
+URLBox::URLBox()
+{
+    set_auto_focusable(false);
+
+    on_change = [this] {
+        highlight_url();
+    };
+}
+
+void URLBox::focusout_event(GUI::FocusEvent& event)
+{
+    set_focus_transition(true);
+
+    highlight_url();
+    GUI::TextBox::focusout_event(event);
+}
+
+void URLBox::focusin_event(GUI::FocusEvent& event)
+{
+    highlight_url();
+    GUI::TextBox::focusin_event(event);
+}
+
+void URLBox::mousedown_event(GUI::MouseEvent& event)
+{
+    if (is_displayonly())
+        return;
+
+    if (event.button() != GUI::MouseButton::Primary)
+        return;
+
+    if (is_focus_transition()) {
+        GUI::TextBox::select_current_line();
+
+        set_focus_transition(false);
+    } else {
+        GUI::TextBox::mousedown_event(event);
+    }
+}
+
+void URLBox::highlight_url()
+{
+    auto url = URL::create_with_url_or_path(text());
+    Vector<GUI::TextDocumentSpan> spans;
+
+    if (url.is_valid() && !is_focused()) {
+        if (url.scheme() == "http" || url.scheme() == "https" || url.scheme() == "gemini") {
+            auto serialized_host = url.serialized_host().release_value_but_fixme_should_propagate_errors().to_deprecated_string();
+            auto host_start = url.scheme().bytes_as_string_view().length() + 3;
+            auto host_length = serialized_host.length();
+
+            // FIXME: Maybe add a generator to use https://publicsuffix.org/list/public_suffix_list.dat
+            //        for now just highlight the whole host
+
+            Gfx::TextAttributes default_format;
+            default_format.color = palette().color(Gfx::ColorRole::PlaceholderText);
+            spans.append({
+                { { 0, 0 }, { 0, host_start } },
+                default_format,
+            });
+
+            Gfx::TextAttributes host_format;
+            host_format.color = palette().color(Gfx::ColorRole::BaseText);
+            spans.append({
+                { { 0, host_start }, { 0, host_start + host_length } },
+                host_format,
+            });
+
+            spans.append({
+                { { 0, host_start + host_length }, { 0, text().length() } },
+                default_format,
+            });
+        } else if (url.scheme() == "file") {
+            Gfx::TextAttributes scheme_format;
+            scheme_format.color = palette().color(Gfx::ColorRole::PlaceholderText);
+            spans.append({
+                { { 0, 0 }, { 0, url.scheme().bytes_as_string_view().length() + 3 } },
+                scheme_format,
+            });
+        }
+    }
+
+    document().set_spans(0, move(spans));
+    update();
+}
+
+}