Auto merge of #27448 - asajeffrey:script-webgl-texture-ownership, r=jdm

Don't delete GL textures created by WebXR

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Currently WebGL assumes it owns any WebGLTexture, and deletes the backing GL texture when the object is GC'd. This isn't valid for textures created by a webxr layer manager, which can result in textures being used after they're deleted.

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #27427
- [x] These changes do not require tests because we don't reftest webxr

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components/script/dom/webgltexture.rs

@@ -29,6 +29,14 @@ pub enum TexParameterValue {
     Bool(bool),
 }
 
+// Textures generated for WebXR are owned by the WebXR device, not by the WebGL thread
+// so the GL texture should not be deleted when the texture is garbage collected.
+#[derive(Clone, Copy, Debug, Eq, JSTraceable, MallocSizeOf, PartialEq)]
+enum WebGLTextureOwner {
+    WebGL,
+    WebXR,
+}
+
 const MAX_LEVEL_COUNT: usize = 31;
 const MAX_FACE_COUNT: usize = 6;
 
@@ -41,6 +49,7 @@ pub struct WebGLTexture {
     /// The target to which this texture was bound the first time
     target: Cell<Option<u32>>,
     is_deleted: Cell<bool>,
+    owner: WebGLTextureOwner,
     /// Stores information about mipmap levels and cubemap faces.
     #[ignore_malloc_size_of = "Arrays are cumbersome"]
     image_info_array: DomRefCell<[Option<ImageInfo>; MAX_LEVEL_COUNT * MAX_FACE_COUNT]>,
@@ -59,12 +68,17 @@ pub struct WebGLTexture {
 }
 
 impl WebGLTexture {
-    fn new_inherited(context: &WebGLRenderingContext, id: WebGLTextureId) -> Self {
+    fn new_inherited(
+        context: &WebGLRenderingContext,
+        id: WebGLTextureId,
+        owner: WebGLTextureOwner,
+    ) -> Self {
         Self {
             webgl_object: WebGLObject::new_inherited(context),
             id: id,
             target: Cell::new(None),
             is_deleted: Cell::new(false),
+            owner: owner,
             immutable_levels: Cell::new(None),
             face_count: Cell::new(0),
             base_mipmap_level: 0,
@@ -87,7 +101,22 @@ impl WebGLTexture {
 
     pub fn new(context: &WebGLRenderingContext, id: WebGLTextureId) -> DomRoot<Self> {
         reflect_dom_object(
-            Box::new(WebGLTexture::new_inherited(context, id)),
+            Box::new(WebGLTexture::new_inherited(
+                context,
+                id,
+                WebGLTextureOwner::WebGL,
+            )),
+            &*context.global(),
+        )
+    }
+
+    pub fn new_webxr(context: &WebGLRenderingContext, id: WebGLTextureId) -> DomRoot<Self> {
+        reflect_dom_object(
+            Box::new(WebGLTexture::new_inherited(
+                context,
+                id,
+                WebGLTextureOwner::WebXR,
+            )),
             &*context.global(),
         )
     }
@@ -216,6 +245,11 @@ impl WebGLTexture {
                 let _ = fb.detach_texture(self);
             }
 
+            // We don't delete textures owned by WebXR
+            if self.owner == WebGLTextureOwner::WebXR {
+                return;
+            }
+
             let cmd = WebGLCommand::DeleteTexture(self.id);
             match operation_fallibility {
                 Operation::Fallible => context.send_command_ignored(cmd),

components/script/dom/xrwebgllayer.rs

@@ -229,7 +229,7 @@ impl XRWebGLLayer {
         // TODO: Cache this texture
         let color_texture_id =
             WebGLTextureId::maybe_new(sub_images.sub_image.as_ref()?.color_texture)?;
-        let color_texture = WebGLTexture::new(context, color_texture_id);
+        let color_texture = WebGLTexture::new_webxr(context, color_texture_id);
         let target = self.texture_target();
 
         // Save the current bindings
@@ -263,7 +263,7 @@ impl XRWebGLLayer {
         if let Some(id) = sub_images.sub_image.as_ref()?.depth_stencil_texture {
             // TODO: Cache this texture
             let depth_stencil_texture_id = WebGLTextureId::maybe_new(id)?;
-            let depth_stencil_texture = WebGLTexture::new(context, depth_stencil_texture_id);
+            let depth_stencil_texture = WebGLTexture::new_webxr(context, depth_stencil_texture_id);
             framebuffer
                 .texture2d_even_if_opaque(
                     constants::DEPTH_STENCIL_ATTACHMENT,