diff --git a/js/xpconnect/wrappers/ChromeObjectWrapper.cpp b/js/xpconnect/wrappers/ChromeObjectWrapper.cpp
index dd4f02817431..a4f6c372a9b0 100644
--- a/js/xpconnect/wrappers/ChromeObjectWrapper.cpp
+++ b/js/xpconnect/wrappers/ChromeObjectWrapper.cpp
@@ -34,7 +34,7 @@ ChromeObjectWrapper::getPropertyDescriptor(JSContext *cx, JSObject *wrapper,
         return true;
 
     // If not, try doing the lookup on the prototype.
-    JSAutoCompartment ac(cx, wrapper);
+    JS_ASSERT(js::IsObjectInContextCompartment(wrapper, cx));
     return JS_GetPropertyDescriptorById(cx, wrapperProto, id, 0, desc);
 }
 
@@ -51,7 +51,7 @@ ChromeObjectWrapper::has(JSContext *cx, JSObject *wrapper, jsid id, bool *bp)
         return true;
 
     // Try the prototype if that failed.
-    JSAutoCompartment ac(cx, wrapper);
+    JS_ASSERT(js::IsObjectInContextCompartment(wrapper, cx));
     JSPropertyDescriptor desc;
     if (!JS_GetPropertyDescriptorById(cx, wrapperProto, id, 0, &desc))
         return false;
@@ -73,7 +73,7 @@ ChromeObjectWrapper::get(JSContext *cx, JSObject *wrapper, JSObject *receiver,
         return true;
 
     // Try the prototype.
-    JSAutoCompartment ac(cx, wrapper);
+    JS_ASSERT(js::IsObjectInContextCompartment(wrapper, cx));
     return js::GetGeneric(cx, wrapperProto, receiver, id, vp);
 }