LibGUI: Allow constructing Variant from FlyString

Libraries/LibGUI/Variant.cpp

@@ -24,6 +24,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <AK/FlyString.h>
 #include <AK/JsonValue.h>
 #include <LibGUI/Variant.h>
 
@@ -128,6 +129,11 @@ Variant::Variant(const char* cstring)
 {
 }
 
+Variant::Variant(const FlyString& value)
+    : Variant(String(value.impl()))
+{
+}
+
 Variant::Variant(const String& value)
     : m_type(Type::String)
 {

Libraries/LibGUI/Variant.h

@@ -43,6 +43,7 @@ public:
     Variant(unsigned);
     Variant(const char*);
     Variant(const String&);
+    Variant(const FlyString&);
     Variant(const Gfx::Bitmap&);
     Variant(const GUI::Icon&);
     Variant(const Gfx::Point&);