diff --git a/components/script/dom/bindings/reflector.rs b/components/script/dom/bindings/reflector.rs
index c888686974e..a58ad301f33 100644
--- a/components/script/dom/bindings/reflector.rs
+++ b/components/script/dom/bindings/reflector.rs
@@ -65,4 +65,12 @@ impl<T: DomGlobalGeneric<crate::DomTypeHolder>> DomGlobal for T {
     }
 }

+pub struct BoxedSelfSize<T>;
+
+impl<T> ReflectedObjectSize for BoxedSelfSize {
+    fn reflected_size(&self) -> usize {
+        std::mem::size_of::<T>() + std::mem::size_of::<Box<T>>()
+    }
+}
+
 pub(crate) use script_bindings::reflector::*;
diff --git a/components/script/dom/blob.rs b/components/script/dom/blob.rs
index 835ab7784a1..dbca3f40b8a 100644
--- a/components/script/dom/blob.rs
+++ b/components/script/dom/blob.rs
@@ -21,7 +21,7 @@ use crate::dom::bindings::codegen::Bindings::BlobBinding;
 use crate::dom::bindings::codegen::Bindings::BlobBinding::BlobMethods;
 use crate::dom::bindings::codegen::UnionTypes::ArrayBufferOrArrayBufferViewOrBlobOrString;
 use crate::dom::bindings::error::{Error, Fallible};
-use crate::dom::bindings::reflector::{DomGlobal, Reflector, reflect_dom_object_with_proto};
+use crate::dom::bindings::reflector::{BoxedSelfSize, DomGlobal, Reflector, reflect_dom_object_with_proto};
 use crate::dom::bindings::root::DomRoot;
 use crate::dom::bindings::serializable::Serializable;
 use crate::dom::bindings::str::DOMString;
@@ -40,7 +40,7 @@ pub(crate) struct Blob {
     blob_id: BlobId,
 }

-impl Blob {
+impl<Actual> Blob<Actual> {
     pub(crate) fn new(global: &GlobalScope, blob_impl: BlobImpl, can_gc: CanGc) -> DomRoot<Blob> {
         Self::new_with_proto(global, None, blob_impl, can_gc)
     }
@@ -90,7 +90,7 @@ impl Blob {
     }
 }

-impl Serializable for Blob {
+impl<Actual> Serializable for Blob<Actual> {
     type Index = BlobIndex;
     type Data = BlobImpl;

diff --git a/components/script_bindings/reflector.rs b/components/script_bindings/reflector.rs
index 390a356d0ea..6a7654c8617 100644
--- a/components/script_bindings/reflector.rs
+++ b/components/script_bindings/reflector.rs
@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

+use js::jsapi::{AddAssociatedMemory, MemoryUse, RemoveAssociatedMemory};
 use js::jsapi::{Heap, JSObject};
 use js::rust::HandleObject;
 use malloc_size_of_derive::MallocSizeOf;
@@ -17,22 +18,23 @@ use crate::{DomTypes, JSTraceable};
 #[derive(MallocSizeOf)]
 #[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
 // If you're renaming or moving this field, update the path in plugins::reflector as well
-pub struct Reflector {
+pub struct Reflector<T: ReflectedObjectSize = ()> {
     #[ignore_malloc_size_of = "defined and measured in rust-mozjs"]
     object: Heap<*mut JSObject>,
+    extra: T,
 }

-unsafe impl js::gc::Traceable for Reflector {
+unsafe impl<T: ReflectedObjectSize> js::gc::Traceable for Reflector<T> {
     unsafe fn trace(&self, _: *mut js::jsapi::JSTracer) {}
 }

-impl PartialEq for Reflector {
-    fn eq(&self, other: &Reflector) -> bool {
+impl<T: ReflectedObjectSize> PartialEq for Reflector<T> {
+    fn eq(&self, other: &Reflector<T>) -> bool {
         self.object.get() == other.object.get()
     }
 }

-impl Reflector {
+impl<T: ReflectedObjectSize> Reflector<T> {
     /// Get the reflector.
     #[inline]
     pub fn get_jsobject(&self) -> HandleObject<'_> {
@@ -57,13 +59,16 @@ impl Reflector {
     pub fn rootable(&self) -> &Heap<*mut JSObject> {
         &self.object
     }
+}

+impl Reflector<()> {
     /// Create an uninitialized `Reflector`.
     // These are used by the bindings and do not need `default()` functions.
     #[expect(clippy::new_without_default)]
     pub fn new() -> Reflector {
         Reflector {
             object: Heap::default(),
+            extra: (),
         }
     }
 }
@@ -90,12 +95,48 @@ pub trait MutDomObject: DomObject {
     unsafe fn init_reflector(&self, obj: *mut JSObject);
 }

-impl MutDomObject for Reflector {
+pub trait ReflectedObjectSize {
+    fn reflected_size(&self) -> usize;
+}
+
+impl ReflectedObjectSize for () {
+    fn reflected_size(&self) -> usize { 0 }
+}
+
+impl<T: ReflectedObjectSize> Drop for Reflector<T> {
+    fn drop(&mut self) {
+        unsafe {
+            RemoveAssociatedMemory(self.object.get(), self.extra.reflected_size(), MemoryUse::DOMBinding);
+        }
+    }
+}
+
+pub trait MutableReflectedObjectSize: ReflectedObjectSize {
+    fn set_reflected_size(&self, new_size: usize);
+}
+
+impl<T: ReflectedObjectSize> MutDomObject for Reflector<T> where Reflector<T>: DomObject {
     unsafe fn init_reflector(&self, obj: *mut JSObject) {
+        unsafe {
+            AddAssociatedMemory(obj, self.extra.reflected_size(), MemoryUse::DOMBinding);
+        }
         self.set_jsobject(obj)
     }
 }

+impl<T: MutableReflectedObjectSize> Reflector<T> {
+    fn update_size(&self, new_size: usize) {
+        unsafe {
+            RemoveAssociatedMemory(self.object.get(), self.extra.reflected_size(), MemoryUse::DOMBinding);
+        }
+        self.extra.set_reflected_size(new_size);
+        unsafe {
+            AddAssociatedMemory(self.object.get(), self.extra.reflected_size(), MemoryUse::DOMBinding);
+        }
+
+    }
+}
+
 pub trait DomGlobalGeneric<D: DomTypes>: DomObject {
     /// Returns the [`GlobalScope`] of the realm that the [`DomObject`] was created in.  If this
     /// object is a `Node`, this will be different from it's owning `Document` if adopted by. For