LibGUI: Add ColorFilterer class

Widgets will inherit from ColorFilterer in order to create the
accessibility CommonMenu

Userland/Libraries/LibGUI/ColorFilterer.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2022, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibGfx/Filters/ColorBlindnessFilter.h>
+
+namespace GUI {
+
+class ColorFilterer {
+public:
+    virtual ~ColorFilterer() = default;
+    virtual void set_color_filter(OwnPtr<Gfx::ColorBlindnessFilter>) = 0;
+
+protected:
+    ColorFilterer() = default;
+};
+
+}