diff --git a/components/script/dom/bindings/proxyhandler.rs b/components/script/dom/bindings/proxyhandler.rs
index c863cc31994b..e400c1678d86 100644
--- a/components/script/dom/bindings/proxyhandler.rs
+++ b/components/script/dom/bindings/proxyhandler.rs
@@ -10,21 +10,37 @@ use dom::bindings::conversions::is_dom_proxy;
 use dom::bindings::utils::delete_property_by_id;
 use js::glue::GetProxyExtra;
 use js::glue::InvokeGetOwnPropertyDescriptor;
-use js::glue::{GetProxyHandler, SetProxyExtra};
+use js::glue::{GetProxyHandler, SetProxyExtra, GetProxyHandlerFamily};
 use js::jsapi::GetObjectProto;
 use js::jsapi::GetStaticPrototype;
 use js::jsapi::JS_GetPropertyDescriptorById;
 use js::jsapi::MutableHandleObject;
 use js::jsapi::{Handle, HandleId, HandleObject, MutableHandle, ObjectOpResult};
-use js::jsapi::{JSContext, JSObject, JSPROP_GETTER, PropertyDescriptor};
+use js::jsapi::{JSContext, JSObject, JSPROP_GETTER, PropertyDescriptor, DOMProxyShadowsResult};
 use js::jsapi::{JSErrNum, JS_StrictPropertyStub};
-use js::jsapi::{JS_DefinePropertyById, JS_NewObjectWithGivenProto};
+use js::jsapi::{JS_DefinePropertyById, JS_NewObjectWithGivenProto, SetDOMProxyInformation};
 use js::jsval::ObjectValue;
 use libc;
 use std::{mem, ptr};
 
 static JSPROXYSLOT_EXPANDO: u32 = 0;
 
+/// Determine if this id shadows any existing properties for this proxy.
+pub unsafe extern "C" fn shadow_check_callback(_cx: *mut JSContext,
+                                               _object: HandleObject,
+                                               _id: HandleId)
+                                               -> DOMProxyShadowsResult {
+    // XXX implement me
+    DOMProxyShadowsResult::ShadowCheckFailed
+}
+
+/// Initialize the infrastructure for DOM proxy objects.
+pub unsafe fn init() {
+    SetDOMProxyInformation(GetProxyHandlerFamily(),
+                           JSPROXYSLOT_EXPANDO,
+                           Some(shadow_check_callback));
+}
+
 /// Invoke the [[GetOwnProperty]] trap (`getOwnPropertyDescriptor`) on `proxy`,
 /// with argument `id` and return the result, if it is not `undefined`.
 /// Otherwise, walk along the prototype chain to find a property with that
diff --git a/components/script/lib.rs b/components/script/lib.rs
index 0f28a2b065c0..ff3715de24cc 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -114,10 +114,10 @@ mod unpremultiplytable;
 mod webdriver_handlers;
 
 use dom::bindings::codegen::RegisterBindings;
-use js::jsapi::{Handle, JSContext, JSObject, SetDOMProxyInformation};
+use dom::bindings::proxyhandler;
+use js::jsapi::{Handle, JSContext, JSObject};
 use script_traits::SWManagerSenders;
 use serviceworker_manager::ServiceWorkerManager;
-use std::ptr;
 use util::opts;
 
 #[cfg(target_os = "linux")]
@@ -164,7 +164,7 @@ fn perform_platform_specific_initialization() {}
 #[allow(unsafe_code)]
 pub fn init(sw_senders: SWManagerSenders) {
     unsafe {
-        SetDOMProxyInformation(ptr::null(), 0, Some(script_thread::shadow_check_callback));
+        proxyhandler::init();
     }
 
     // Spawn the service worker manager passing the constellation sender
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 33f7da41d203..e0e451bc1204 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -59,7 +59,6 @@ use hyper_serde::Serde;
 use ipc_channel::ipc::{self, IpcSender};
 use ipc_channel::router::ROUTER;
 use js::glue::GetWindowProxyClass;
-use js::jsapi::{DOMProxyShadowsResult, HandleId, HandleObject};
 use js::jsapi::{JSAutoCompartment, JSContext, JS_SetWrapObjectCallbacks};
 use js::jsapi::{JSTracer, SetWindowProxyClass};
 use js::jsval::UndefinedValue;
@@ -484,12 +483,6 @@ impl ScriptThreadFactory for ScriptThread {
     }
 }
 
-pub unsafe extern "C" fn shadow_check_callback(_cx: *mut JSContext,
-    _object: HandleObject, _id: HandleId) -> DOMProxyShadowsResult {
-    // XXX implement me
-    DOMProxyShadowsResult::ShadowCheckFailed
-}
-
 impl ScriptThread {
     pub fn page_headers_available(id: &PipelineId, subpage: Option<&SubpageId>, metadata: Option<Metadata>)
                                   -> Option<ParserRoot> {
diff --git a/components/servo/Cargo.lock b/components/servo/Cargo.lock
index 6112465b86a7..20b8ba925870 100644
--- a/components/servo/Cargo.lock
+++ b/components/servo/Cargo.lock
@@ -1086,7 +1086,7 @@ dependencies = [
 [[package]]
 name = "js"
 version = "0.1.3"
-source = "git+https://github.com/servo/rust-mozjs#daffcfb1e0568b3e67dda331b487cc9fd8a202cb"
+source = "git+https://github.com/servo/rust-mozjs#a4a693bf41fc67e839f3a5e8219d872f5c675b5f"
 dependencies = [
  "cmake 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index 2fceab3eaa1b..0ad4c0d05bd2 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -994,7 +994,7 @@ dependencies = [
 [[package]]
 name = "js"
 version = "0.1.3"
-source = "git+https://github.com/servo/rust-mozjs#daffcfb1e0568b3e67dda331b487cc9fd8a202cb"
+source = "git+https://github.com/servo/rust-mozjs#a4a693bf41fc67e839f3a5e8219d872f5c675b5f"
 dependencies = [
  "cmake 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",