Add declarative V8 receiver access checks and Window brand validation. Authorize SameObject getters before cache reads, preserve captured objects for retired Realms, and materialize child proxies for the actual accessing context with isolated facade tokens.
Generate stateless method and accessor tables with receiver checks and native
value callbacks. Cache FunctionTemplates per isolate and use V8's per-context
function instances, without retaining target Windows or observer realms.
Cover function identity, realm prototypes, descriptors, receiver validation,
exception and termination propagation, and context collection.
Use native Web API identity for ResizeObserver and IntersectionObserver targets and roots, accepting genuine cross-realm objects and registered native proxies while rejecting forged, inherited and author-Proxy values. Validate root membership during dictionary conversion, before later getters, and resolve native targets without reading public nodeType properties.
A 204-case regression matrix covers both observer interfaces and realms, native proxy acceptance, invalid targets, poisoned properties, option conversion order and original exception identity.
Expose the backing-object lookup from the existing native brand layer rather than unwrapping author Proxies in DOM callbacks. Extend its existing identity tests for cross-realm objects, forged objects, registered native Proxies, outer author Proxies and revocation.
ldm0