avm2: Implement `flash.display.PixelSnapping` (#5718)

* Add flash.display.PixelSnapping enum class

* Run 'cargo format --all'

* Add 'final' class attribute

core/src/avm2/globals.rs

@@ -816,6 +816,11 @@ pub fn load_player_globals<'gc>(
         flash::display::bitmapdata::create_class(mc),
         script
     );
+    class(
+        activation,
+        flash::display::pixelsnapping::create_class(mc),
+        script,
+    )?;
 
     // package `flash.geom`
     avm2_system_class!(

core/src/avm2/globals/flash/display.rs

@@ -14,6 +14,7 @@ pub mod jointstyle;
 pub mod linescalemode;
 pub mod loaderinfo;
 pub mod movieclip;
+pub mod pixelsnapping;
 pub mod scene;
 pub mod shape;
 pub mod simplebutton;

core/src/avm2/globals/flash/display/pixelsnapping.rs

@@ -0,0 +1,53 @@
+//! `flash.display.PixelSnapping` builtin/prototype
+
+use crate::avm2::activation::Activation;
+use crate::avm2::class::{Class, ClassAttributes};
+use crate::avm2::method::Method;
+use crate::avm2::names::{Namespace, QName};
+use crate::avm2::object::Object;
+use crate::avm2::value::Value;
+use crate::avm2::Error;
+use gc_arena::{GcCell, MutationContext};
+
+/// Implements `flash.display.PixelSnapping`'s instance constructor.
+pub fn instance_init<'gc>(
+    activation: &mut Activation<'_, 'gc, '_>,
+    this: Option<Object<'gc>>,
+    _args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error> {
+    if let Some(this) = this {
+        activation.super_init(this, &[])?;
+    }
+
+    Ok(Value::Undefined)
+}
+
+/// Implements `flash.display.PixelSnapping`'s class constructor.
+pub fn class_init<'gc>(
+    _activation: &mut Activation<'_, 'gc, '_>,
+    _this: Option<Object<'gc>>,
+    _args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error> {
+    Ok(Value::Undefined)
+}
+
+/// Construct `PixelSnapping`'s class.
+pub fn create_class<'gc>(mc: MutationContext<'gc, '_>) -> GcCell<'gc, Class<'gc>> {
+    let class = Class::new(
+        QName::new(Namespace::package("flash.display"), "PixelSnapping"),
+        Some(QName::new(Namespace::public(), "Object").into()),
+        Method::from_builtin(instance_init, "<PixelSnapping instance initializer>", mc),
+        Method::from_builtin(class_init, "<PixelSnapping class initializer>", mc),
+        mc,
+    );
+
+    let mut write = class.write(mc);
+
+    write.set_attributes(ClassAttributes::SEALED | ClassAttributes::FINAL);
+
+    const CONSTANTS: &[(&str, &str)] =
+        &[("ALWAYS", "always"), ("AUTO", "auto"), ("NEVER", "never")];
+    write.define_public_constant_string_class_traits(CONSTANTS);
+
+    class
+}