LibGfx: Add ImageCursor type and Cursor variant

Besides standard cursors, we also need to support custom images. For
now, everything still uses StandardCursor.

Libraries/LibGfx/Cursor.cpp

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibGfx/Cursor.h>
+#include <LibIPC/Decoder.h>
+#include <LibIPC/Encoder.h>
+
+namespace Gfx {
+
+bool ImageCursor::operator==(ImageCursor const& other) const
+{
+    return hotspot == other.hotspot
+        && bitmap.bitmap() == other.bitmap.bitmap();
+}
+
+}
+
+namespace IPC {
+
+template<>
+ErrorOr<void> encode(Encoder& encoder, Gfx::ImageCursor const& image_cursor)
+{
+    TRY(encoder.encode(image_cursor.bitmap));
+    TRY(encoder.encode(image_cursor.hotspot));
+    return {};
+}
+
+template<>
+ErrorOr<Gfx::ImageCursor> decode(Decoder& decoder)
+{
+    Gfx::ImageCursor result;
+    result.bitmap = TRY(decoder.decode<Gfx::ShareableBitmap>());
+    result.hotspot = TRY(decoder.decode<Gfx::IntPoint>());
+    return result;
+}
+
+}