avm1/avm2: Add AvmString::from_static_wstr and use it

Replaces the old `From<&'static WStr>` impl on AvmString

core/src/avm1/globals/bevel_filter.rs

@@ -515,7 +515,7 @@ fn method<'gc>(
         }
         GET_TYPE => {
             let type_: &WStr = this.type_().into();
-            AvmString::from(type_).into()
+            AvmString::from_static_wstr(activation.gc(), type_).into()
         }
         SET_TYPE => {
             this.set_type(activation, args.get(0))?;

core/src/avm1/globals/displacement_map_filter.rs

@@ -418,7 +418,7 @@ fn method<'gc>(
         }
         GET_MODE => {
             let mode: &WStr = this.mode().into();
-            AvmString::from(mode).into()
+            AvmString::from_static_wstr(activation.gc(), mode).into()
         }
         SET_MODE => {
             this.set_mode(activation, args.get(0))?;

core/src/avm1/globals/gradient_filter.rs

@@ -506,7 +506,7 @@ fn method<'gc>(
         }
         GET_TYPE => {
             let type_: &WStr = this.type_().into();
-            AvmString::from(type_).into()
+            AvmString::from_static_wstr(activation.gc(), type_).into()
         }
         SET_TYPE => {
             this.set_type(activation, args.get(0))?;

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

@@ -6,6 +6,7 @@ use crate::avm2::globals::flash::display::display_object::initialize_for_allocat
 use crate::avm2::object::{BitmapDataObject, ClassObject, Object, TObject};
 use crate::avm2::value::Value;
 use crate::avm2::Error;
+use crate::string::AvmString;
 use ruffle_render::bitmap::PixelSnapping;
 use ruffle_wstr::WStr;
 
@@ -156,15 +157,18 @@ pub fn set_bitmap_data<'gc>(
 
 /// Stub `Bitmap.pixelSnapping`'s getter
 pub fn get_pixel_snapping<'gc>(
-    _activation: &mut Activation<'_, 'gc>,
+    activation: &mut Activation<'_, 'gc>,
     this: Value<'gc>,
     _args: &[Value<'gc>],
 ) -> Result<Value<'gc>, Error<'gc>> {
     let this = this.as_object().unwrap();
 
     if let Some(bitmap) = this.as_display_object().and_then(|dobj| dobj.as_bitmap()) {
         let value: &WStr = bitmap.pixel_snapping().into();
-        return Ok(Value::String(value.into()));
+        return Ok(Value::String(AvmString::from_static_wstr(
+            activation.gc(),
+            value,
+        )));
     }
     Ok(Value::Undefined)
 }

core/src/string/avm_string.rs

@@ -68,6 +68,14 @@ impl<'gc> AvmString<'gc> {
         }
     }
 
+    pub fn from_static_wstr(gc_context: &Mutation<'gc>, string: &'static WStr) -> Self {
+        let repr = AvmStringRepr::from_raw_static(string, false);
+
+        Self {
+            source: Source::Managed(Gc::new(gc_context, repr)),
+        }
+    }
+
     pub fn substring(mc: &Mutation<'gc>, string: AvmString<'gc>, start: usize, end: usize) -> Self {
         match string.source {
             Source::Managed(repr) => {
@@ -175,15 +183,6 @@ impl From<&'static str> for AvmString<'_> {
     }
 }
 
-impl From<&'static WStr> for AvmString<'_> {
-    #[inline]
-    fn from(str: &'static WStr) -> Self {
-        Self {
-            source: Source::Static(str),
-        }
-    }
-}
-
 impl Deref for AvmString<'_> {
     type Target = WStr;
     #[inline]