--- a/js/ipc/JavaScriptChild.cpp
+++ b/js/ipc/JavaScriptChild.cpp
@@ -135,18 +135,171 @@ JavaScriptChild::fail(JSContext *cx, Ret
 bool
 JavaScriptChild::ok(ReturnStatus *rs)
 {
     *rs = ReturnStatus(true, JSVariant(void_t()));
     return true;
 }
 
 bool
-JavaScriptChild::AnswerHas(const ObjectId &objId, const nsString &id,
-                               ReturnStatus *rs, bool *bp)
+JavaScriptChild::AnswerPreventExtensions(const ObjectId &objId, ReturnStatus *rs)
+{
+    AutoSafeJSContext cx;
+    JSAutoRequest request(cx);
+
+    RootedObject obj(cx, findObject(objId));
+    if (!obj)
+        return false;
+
+    JSAutoCompartment comp(cx, obj);
+    if (!JS_PreventExtensions(cx, obj))
+        return fail(cx, rs);
+
+    return ok(rs);
+}
+
+static void
+EmptyDesc(PPropertyDescriptor *desc)
+{
+    desc->objId() = 0;
+    desc->attrs() = 0;
+    desc->shortid() = 0;
+    desc->value() = void_t();
+    desc->getter() = 0;
+    desc->setter() = 0;
+}
+
+bool
+JavaScriptChild::AnswerGetPropertyDescriptor(const ObjectId &objId, const nsString &id,
+                                             const uint32_t &flags, ReturnStatus *rs,
+                                             PPropertyDescriptor *out)
+{
+    AutoSafeJSContext cx;
+    JSAutoRequest request(cx);
+
+    EmptyDesc(out);
+
+    RootedObject obj(cx, findObject(objId));
+    if (!obj)
+        return false;
+
+    JSAutoCompartment comp(cx, obj);
+
+    RootedId internedId(cx);
+    if (!convertGeckoStringToId(cx, id, &internedId))
+        return fail(cx, rs);
+
+    JSPropertyDescriptor desc;
+    if (!JS_GetPropertyDescriptorById(cx, obj, internedId, flags, &desc))
+        return fail(cx, rs);
+
+    if (!desc.obj)
+        return ok(rs);
+
+    if (!fromDescriptor(cx, desc, out))
+        return fail(cx, rs);
+
+    return ok(rs);
+}
+
+bool
+JavaScriptChild::AnswerGetOwnPropertyDescriptor(const ObjectId &objId, const nsString &id,
+                                                const uint32_t &flags, ReturnStatus *rs,
+                                                PPropertyDescriptor *out)
+{
+    AutoSafeJSContext cx;
+    JSAutoRequest request(cx);
+
+    EmptyDesc(out);
+
+    RootedObject obj(cx, findObject(objId));
+    if (!obj)
+        return false;
+
+    JSAutoCompartment comp(cx, obj);
+
+    RootedId internedId(cx);
+    if (!convertGeckoStringToId(cx, id, &internedId))
+        return fail(cx, rs);
+
+    JSPropertyDescriptor desc;
+    if (!JS_GetPropertyDescriptorById(cx, obj, internedId, flags, &desc))
+        return fail(cx, rs);
+
+    if (desc.obj != obj)
+        return ok(rs);
+
+    if (!fromDescriptor(cx, desc, out))
+        return fail(cx, rs);
+
+    return ok(rs);
+}
+
+bool
+JavaScriptChild::AnswerDefineProperty(const ObjectId &objId, const nsString &id,
+                                      const PPropertyDescriptor &descriptor, ReturnStatus *rs)
+{
+    AutoSafeJSContext cx;
+    JSAutoRequest request(cx);
+
+    RootedObject obj(cx, findObject(objId));
+    if (!obj)
+        return false;
+
+    JSAutoCompartment comp(cx, obj);
+
+    RootedId internedId(cx);
+    if (!convertGeckoStringToId(cx, id, &internedId))
+        return fail(cx, rs);
+
+    JSPropertyDescriptor desc;
+    if (!toDescriptor(cx, descriptor, &desc))
+        return false;
+
+    RootedValue v(cx, desc.value);
+    if (!js::CheckDefineProperty(cx, obj, internedId, v, desc.getter, desc.setter, desc.attrs) ||
+        !JS_DefinePropertyById(cx, obj, internedId, v, desc.getter, desc.setter, desc.attrs))
+    {
+        return fail(cx, rs);
+    }
+
+    return ok(rs);
+}
+
+bool
+JavaScriptChild::AnswerDelete(const ObjectId &objId, const nsString &id, ReturnStatus *rs,
+                              bool *success)
+{
+    AutoSafeJSContext cx;
+    JSAutoRequest request(cx);
+
+    RootedObject obj(cx, findObject(objId));
+    if (!obj)
+        return false;
+
+    JSAutoCompartment comp(cx, obj);
+
+    RootedId internedId(cx);
+    if (!convertGeckoStringToId(cx, id, &internedId))
+        return fail(cx, rs);
+
+    RootedValue v(cx);
+    if (!JS_DeletePropertyById2(cx, obj, internedId, v.address()))
+        return fail(cx, rs);
+
+    JSBool b;
+    if (!JS_ValueToBoolean(cx, v, &b))
+        return fail(cx, rs);
+    *success = !!b;
+
+    return ok(rs);
+}
+
+bool
+JavaScriptChild::AnswerHas(const ObjectId &objId, const nsString &id, ReturnStatus *rs, bool *bp)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
 
@@ -160,18 +313,17 @@ JavaScriptChild::AnswerHas(const ObjectI
     if (!JS_HasPropertyById(cx, obj, internedId, &found))
         return fail(cx, rs);
     *bp = !!found;
 
     return ok(rs);
 }
 
 bool
-JavaScriptChild::AnswerHasOwn(const ObjectId &objId, const nsString &id,
-                                  ReturnStatus *rs, bool *bp)
+JavaScriptChild::AnswerHasOwn(const ObjectId &objId, const nsString &id, ReturnStatus *rs, bool *bp)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
 
@@ -185,23 +337,24 @@ JavaScriptChild::AnswerHasOwn(const Obje
     if (!JS_GetPropertyDescriptorById(cx, obj, internedId, 0, &desc))
         return fail(cx, rs);
     *bp = (desc.obj == obj);
 
     return ok(rs);
 }
 
 bool
-JavaScriptChild::AnswerGet(const ObjectId &objId, const ObjectId &receiverId,
-                               const nsString &id,
-                               ReturnStatus *rs, JSVariant *result)
+JavaScriptChild::AnswerGet(const ObjectId &objId, const ObjectId &receiverId, const nsString &id,
+                           ReturnStatus *rs, JSVariant *result)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
+    *result = void_t();
+
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
 
     RootedObject receiver(cx, findObject(receiverId));
     if (!receiver)
         return false;
 
@@ -217,20 +370,19 @@ JavaScriptChild::AnswerGet(const ObjectI
 
     if (!toVariant(cx, val, result))
         return fail(cx, rs);
 
     return ok(rs);
 }
 
 bool
-JavaScriptChild::AnswerSet(const ObjectId &objId, const ObjectId &receiverId,
-                               const nsString &id, const bool &strict,
-                               const JSVariant &value,
-                               ReturnStatus *rs, JSVariant *result)
+JavaScriptChild::AnswerSet(const ObjectId &objId, const ObjectId &receiverId, const nsString &id,
+                           const bool &strict, const JSVariant &value, ReturnStatus *rs,
+                           JSVariant *result)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
     // The outparam will be written to the buffer, so it must be set even if
     // the parent won't read it.
     *result = void_t();
 
@@ -259,21 +411,38 @@ JavaScriptChild::AnswerSet(const ObjectI
 
     if (!toVariant(cx, val, result))
         return fail(cx, rs);
 
     return ok(rs);
 }
 
 bool
-JavaScriptChild::AnswerCall(const ObjectId &objId,
-                            const nsTArray<JSParam> &argv,
-                            ReturnStatus *rs,
-                            JSVariant *result,
-                            nsTArray<JSParam> *outparams)
+JavaScriptChild::AnswerIsExtensible(const ObjectId &objId, ReturnStatus *rs, bool *result)
+{
+    AutoSafeJSContext cx;
+    JSAutoRequest request(cx);
+
+    *result = false;
+
+    RootedObject obj(cx, findObject(objId));
+    if (!obj)
+        return false;
+
+    JSBool extensible;
+    if (!JS_IsExtensible(cx, obj, &extensible))
+        return fail(cx, rs);
+
+    *result = !!extensible;
+    return true;
+}
+
+bool
+JavaScriptChild::AnswerCall(const ObjectId &objId, const nsTArray<JSParam> &argv, ReturnStatus *rs,
+                            JSVariant *result, nsTArray<JSParam> *outparams)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
     // The outparam will be written to the buffer, so it must be set even if
     // the parent won't read it.
     *result = void_t();
 
@@ -286,18 +455,18 @@ JavaScriptChild::AnswerCall(const Object
     RootedValue objv(cx);
     if (!toValue(cx, argv[0], &objv))
         return fail(cx, rs);
 
     JSAutoCompartment comp(cx, &objv.toObject());
 
     *result = JSVariant(void_t());
 
-    JS::AutoValueVector vals(cx);
-    JS::AutoValueVector outobjects(cx);
+    AutoValueVector vals(cx);
+    AutoValueVector outobjects(cx);
     for (size_t i = 0; i < argv.Length(); i++) {
         if (argv[i].type() == JSParam::Tvoid_t) {
             // This is an outparam.
             JSCompartment *compartment = js::GetContextCompartment(cx);
             RootedObject global(cx, JS_GetGlobalForCompartmentOrNull(cx, compartment));
             RootedObject obj(cx, xpc::NewOutObject(cx, global));
             if (!obj)
                 return fail(cx, rs);
@@ -358,152 +527,48 @@ JavaScriptChild::AnswerCall(const Object
         if (!toVariant(cx, vals[i], &variant))
             return fail(cx, rs);
         outparams->ReplaceElementAt(i, JSParam(variant));
     }
 
     return ok(rs);
 }
 
-
 bool
-JavaScriptChild::AnswerInstanceOf(const ObjectId &objId,
-                                  const JSIID &iid,
-                                  ReturnStatus *rs,
-                                  bool *instanceof)
-{
-    AutoSafeJSContext cx;
-    JSAutoRequest request(cx);
-
-    RootedObject obj(cx, findObject(objId));
-    if (!obj)
-        return false;
-
-    JSAutoCompartment comp(cx, obj);
-
-    nsID nsiid;
-    ConvertID(iid, &nsiid);
-
-    nsresult rv = xpc::HasInstance(cx, obj, &nsiid, instanceof);
-    if (rv != NS_OK)
-        return fail(cx, rs);
-
-    return ok(rs);
-}
-
-void
-EmptyDesc(PPropertyDescriptor *desc)
-{
-    desc->objId() = 0;
-    desc->attrs() = 0;
-    desc->shortid() = 0;
-    desc->value() = void_t();
-    desc->getter() = 0;
-    desc->setter() = 0;
-}
-
-bool
-JavaScriptChild::AnswerGetPropertyDescriptor(const ObjectId &objId,
-                                             const nsString &id,
-                                             const uint32_t &flags,
-                                             ReturnStatus *rs,
-                                             PPropertyDescriptor *out)
+JavaScriptChild::AnswerObjectClassIs(const ObjectId &objId, const uint32_t &classValue,
+                                     bool *result)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
 
     JSAutoCompartment comp(cx, obj);
 
-    RootedId internedId(cx);
-    if (!convertGeckoStringToId(cx, id, &internedId))
-        return fail(cx, rs);
-
-    JSPropertyDescriptor desc;
-    if (!JS_GetPropertyDescriptorById(cx, obj, internedId, flags, &desc))
-        return fail(cx, rs);
+    *result = js_ObjectClassIs(cx, obj, (js::ESClassValue)classValue);
 
-    if (!desc.obj) {
-        EmptyDesc(out);
-        return ok(rs);
-    }
-
-    if (!fromDescriptor(cx, desc, out))
-        return fail(cx, rs);
-
-    return ok(rs);
+    return true;
 }
 
 bool
-JavaScriptChild::AnswerGetOwnPropertyDescriptor(const ObjectId &objId,
-                                                const nsString &id,
-                                                const uint32_t &flags,
-                                                ReturnStatus *rs,
-                                                PPropertyDescriptor *out)
+JavaScriptChild::AnswerClassName(const ObjectId &objId, nsString *name)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
 
     JSAutoCompartment comp(cx, obj);
 
-    RootedId internedId(cx);
-    if (!convertGeckoStringToId(cx, id, &internedId))
-        return fail(cx, rs);
-
-    JSPropertyDescriptor desc;
-    if (!JS_GetPropertyDescriptorById(cx, obj, internedId, flags, &desc))
-        return fail(cx, rs);
-
-    if (desc.obj != obj) {
-        EmptyDesc(out);
-        return ok(rs);
-    }
-
-    if (!fromDescriptor(cx, desc, out))
-        return fail(cx, rs);
-
-    return ok(rs);
-}
-
-bool
-JavaScriptChild::AnswerDefineProperty(const ObjectId &objId, const nsString &id,
-                                      const PPropertyDescriptor &descriptor, ReturnStatus *rs)
-{
-    AutoSafeJSContext cx;
-    JSAutoRequest request(cx);
-
-    RootedObject obj(cx, findObject(objId));
-    if (!obj)
-        return false;
-
-    JSAutoCompartment comp(cx, obj);
-
-    RootedId internedId(cx);
-    if (!convertGeckoStringToId(cx, id, &internedId))
-        return fail(cx, rs);
-
-    JSPropertyDescriptor desc;
-    if (!toDescriptor(cx, descriptor, &desc))
-        return false;
-
-    RootedValue v(cx, desc.value);
-    if (!js::CheckDefineProperty(cx, obj, internedId, v, desc.getter, desc.setter, desc.attrs) ||
-        !JS_DefinePropertyById(cx, obj, internedId, v, desc.getter, desc.setter, desc.attrs))
-    {
-        return fail(cx, rs);
-    }
-
-    return ok(rs);
+    *name = NS_ConvertASCIItoUTF16(js_ObjectClassName(cx, obj));
+    return true;
 }
 
 bool
 JavaScriptChild::AnswerGetPropertyNames(const ObjectId &objId, const uint32_t &flags,
                                         ReturnStatus *rs, nsTArray<nsString> *names)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
@@ -525,141 +590,29 @@ JavaScriptChild::AnswerGetPropertyNames(
 
         names->AppendElement(name);
     }
 
     return ok(rs);
 }
 
 bool
-JavaScriptChild::AnswerKeys(const ObjectId &objId,
-                            ReturnStatus *rs,
-                            nsTArray<nsString> *names)
-{
-    AutoSafeJSContext cx;
-    JSAutoRequest request(cx);
-
-    RootedObject obj(cx, findObject(objId));
-    if (!obj)
-        return false;
-
-    JSAutoCompartment comp(cx, obj);
-
-    AutoIdVector props(cx);
-    if (!js::GetPropertyNames(cx, obj, JSITER_OWNONLY, &props))
-        return fail(cx, rs);
-
-    for (size_t i = 0; i < props.length(); i++) {
-        nsString name;
-        if (!convertIdToGeckoString(cx, props.handleAt(i), &name))
-            return false;
-
-        names->AppendElement(name);
-    }
-
-    return ok(rs);
-}
-
-bool
-JavaScriptChild::AnswerObjectClassIs(const ObjectId &objId,
-                                     const uint32_t &classValue,
-                                     bool *result)
-{
-    AutoSafeJSContext cx;
-    JSAutoRequest request(cx);
-
-    RootedObject obj(cx, findObject(objId));
-    if (!obj)
-        return false;
-
-    JSAutoCompartment comp(cx, obj);
-
-    *result = js_ObjectClassIs(cx, obj, (js::ESClassValue)classValue);
-
-    return true;
-}
-
-bool
-JavaScriptChild::AnswerClassName(const ObjectId &objId,
-                                 nsString *name)
+JavaScriptChild::AnswerInstanceOf(const ObjectId &objId, const JSIID &iid, ReturnStatus *rs,
+                                  bool *instanceof)
 {
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
 
     JSAutoCompartment comp(cx, obj);
 
-    *name = NS_ConvertASCIItoUTF16(js_ObjectClassName(cx, obj));
-    return true;
-}
-
-bool
-JavaScriptChild::AnswerIsExtensible(const ObjectId &objId,
-                                    ReturnStatus *rs,
-                                    bool *result)
-{
-    AutoSafeJSContext cx;
-    JSAutoRequest request(cx);
-
-    *result = false;
-
-    RootedObject obj(cx, findObject(objId));
-    if (!obj)
-        return false;
+    nsID nsiid;
+    ConvertID(iid, &nsiid);
 
-    JSBool extensible;
-    if (!JS_IsExtensible(cx, obj, &extensible))
-        return fail(cx, rs);
-
-    *result = !!extensible;
-    return true;
-}
-
-bool
-JavaScriptChild::AnswerPreventExtensions(const ObjectId &objId,
-                                         ReturnStatus *rs)
-{
-    AutoSafeJSContext cx;
-    JSAutoRequest request(cx);
-
-    RootedObject obj(cx, findObject(objId));
-    if (!obj)
-        return false;
-
-    JSAutoCompartment comp(cx, obj);
-    if (!JS_PreventExtensions(cx, obj))
+    nsresult rv = xpc::HasInstance(cx, obj, &nsiid, instanceof);
+    if (rv != NS_OK)
         return fail(cx, rs);
 
     return ok(rs);
 }
-
-
-bool
-JavaScriptChild::AnswerDelete(const ObjectId &objId, const nsString &id,
-                              ReturnStatus *rs, bool *success)
-{
-    AutoSafeJSContext cx;
-    JSAutoRequest request(cx);
-
-    JSObject *obj = findObject(objId);
-    if (!obj)
-        return false;
-
-    JSAutoCompartment comp(cx, obj);
-
-    RootedId internedId(cx);
-    if (!convertGeckoStringToId(cx, id, &internedId))
-        return fail(cx, rs);
-
-    RootedValue v(cx);
-    if (!JS_DeletePropertyById2(cx, obj, internedId, v.address()))
-        return fail(cx, rs);
-
-    JSBool b;
-    if (!JS_ValueToBoolean(cx, v, &b))
-        return fail(cx, rs);
-    *success = !!b;
-
-    return ok(rs);
-}

--- a/js/ipc/JavaScriptChild.h
+++ b/js/ipc/JavaScriptChild.h
@@ -22,70 +22,55 @@ class JavaScriptChild
     JavaScriptChild(JSRuntime *rt);
     ~JavaScriptChild();
 
     bool init();
     void trace(JSTracer *trc);
 
     bool RecvDropObject(const ObjectId &objId);
 
+    bool AnswerPreventExtensions(const ObjectId &objId, ReturnStatus *rs);
+    bool AnswerGetPropertyDescriptor(const ObjectId &objId, const nsString &id,
+                                     const uint32_t &flags, ReturnStatus *rs,
+                                     PPropertyDescriptor *out);
+    bool AnswerGetOwnPropertyDescriptor(const ObjectId &objId,
+                                        const nsString &id,
+                                        const uint32_t &flags,
+                                        ReturnStatus *rs,
+                                        PPropertyDescriptor *out);
+    bool AnswerDefineProperty(const ObjectId &objId, const nsString &id,
+                              const PPropertyDescriptor &flags,
+                              ReturnStatus *rs);
+    bool AnswerDelete(const ObjectId &objId, const nsString &id,
+                      ReturnStatus *rs, bool *success);
+
     bool AnswerHas(const ObjectId &objId, const nsString &id,
                        ReturnStatus *rs, bool *bp);
     bool AnswerHasOwn(const ObjectId &objId, const nsString &id,
                           ReturnStatus *rs, bool *bp);
     bool AnswerGet(const ObjectId &objId, const ObjectId &receiverId,
                        const nsString &id,
                        ReturnStatus *rs, JSVariant *result);
     bool AnswerSet(const ObjectId &objId, const ObjectId &receiverId,
-                       const nsString &id, const bool &strict,
-                       const JSVariant &value,
-                       ReturnStatus *rs, JSVariant *result);
-    bool AnswerCall(const ObjectId &objId,
-                        const nsTArray<JSParam> &argv,
-                        ReturnStatus *rs,
-                        JSVariant *result,
-                        nsTArray<JSParam> *outparams);
+                   const nsString &id, const bool &strict,
+                   const JSVariant &value, ReturnStatus *rs, JSVariant *result);
 
-    bool AnswerInstanceOf(const ObjectId &objId,
-                          const JSIID &iid,
-                          ReturnStatus *rs,
-                          bool *instanceof);
-    bool AnswerGetPropertyDescriptor(const ObjectId &objId,
-                                     const nsString &id,
-                                     const uint32_t &flags,
-                                     ReturnStatus *rs,
-                                     PPropertyDescriptor *out);
-    bool AnswerGetOwnPropertyDescriptor(const ObjectId &objId,
-                                        const nsString &id,
-                                        const uint32_t &flags,
-                                        ReturnStatus *rs,
-                                        PPropertyDescriptor *out);
-    bool AnswerDefineProperty(const ObjectId &objId,
-                              const nsString &id,
-                              const PPropertyDescriptor &flags,
-                              ReturnStatus *rs);
-    bool AnswerGetPropertyNames(const ObjectId &objId,
-                                const uint32_t &flags,
-                                ReturnStatus *rs,
-                                nsTArray<nsString> *names);
-    bool AnswerKeys(const ObjectId &objId,
-                    ReturnStatus *rs,
-                    nsTArray<nsString> *names);
-    bool AnswerObjectClassIs(const ObjectId &objId,
-                             const uint32_t &classValue,
+    bool AnswerIsExtensible(const ObjectId &objId, ReturnStatus *rs,
+                            bool *result);
+    bool AnswerCall(const ObjectId &objId, const nsTArray<JSParam> &argv,
+                    ReturnStatus *rs, JSVariant *result,
+                    nsTArray<JSParam> *outparams);
+    bool AnswerObjectClassIs(const ObjectId &objId, const uint32_t &classValue,
                              bool *result);
-    bool AnswerClassName(const ObjectId &objId,
-                             nsString *result);
-    bool AnswerIsExtensible(const ObjectId &objId,
-                            ReturnStatus *rs,
-                            bool *result);
-    bool AnswerPreventExtensions(const ObjectId &objId,
-                                 ReturnStatus *rs);
-    bool AnswerDelete(const ObjectId &objId, const nsString &id,
-                      ReturnStatus *rs, bool *success);
+    bool AnswerClassName(const ObjectId &objId, nsString *result);
+
+    bool AnswerGetPropertyNames(const ObjectId &objId, const uint32_t &flags,
+                                ReturnStatus *rs, nsTArray<nsString> *names);
+    bool AnswerInstanceOf(const ObjectId &objId, const JSIID &iid,
+                          ReturnStatus *rs, bool *instanceof);
 
   protected:
     JSObject *unwrap(JSContext *cx, ObjectId id);
 
   private:
     bool makeId(JSContext *cx, JSObject *obj, ObjectId *idp);
     bool fail(JSContext *cx, ReturnStatus *rs);
     bool ok(ReturnStatus *rs);

--- a/js/ipc/JavaScriptParent.cpp
+++ b/js/ipc/JavaScriptParent.cpp
@@ -55,16 +55,17 @@ class CPOWProxyHandler : public BaseProx
     CPOWProxyHandler()
       : BaseProxyHandler(&sCPOWProxyHandler) {}
     virtual ~CPOWProxyHandler() {}
 
     virtual bool finalizeInBackground(Value priv) MOZ_OVERRIDE {
         return false;
     }
 
+    virtual bool preventExtensions(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE;
     virtual bool getPropertyDescriptor(JSContext *cx, HandleObject proxy, HandleId id,
                                        PropertyDescriptor *desc, unsigned flags) MOZ_OVERRIDE;
     virtual bool getOwnPropertyDescriptor(JSContext *cx, HandleObject proxy,
                                           HandleId id, PropertyDescriptor *desc, unsigned flags) MOZ_OVERRIDE;
     virtual bool defineProperty(JSContext *cx, HandleObject proxy, HandleId id,
                                 PropertyDescriptor *desc) MOZ_OVERRIDE;
     virtual bool getOwnPropertyNames(JSContext *cx, HandleObject proxy,
                                      AutoIdVector &props) MOZ_OVERRIDE;
@@ -74,29 +75,46 @@ class CPOWProxyHandler : public BaseProx
     virtual bool has(JSContext *cx, HandleObject proxy, HandleId id, bool *bp) MOZ_OVERRIDE;
     virtual bool hasOwn(JSContext *cx, HandleObject proxy, HandleId id, bool *bp) MOZ_OVERRIDE;
     virtual bool get(JSContext *cx, HandleObject proxy, HandleObject receiver,
                      HandleId id, MutableHandleValue vp) MOZ_OVERRIDE;
     virtual bool set(JSContext *cx, JS::HandleObject proxy, JS::HandleObject receiver,
                      JS::HandleId id, bool strict, JS::MutableHandleValue vp) MOZ_OVERRIDE;
     virtual bool keys(JSContext *cx, HandleObject proxy, AutoIdVector &props) MOZ_OVERRIDE;
 
+    virtual bool isExtensible(JSContext *cx, HandleObject proxy, bool *extensible) MOZ_OVERRIDE;
     virtual bool call(JSContext *cx, HandleObject proxy, const CallArgs &args) MOZ_OVERRIDE;
-    virtual void finalize(JSFreeOp *fop, JSObject *proxy) MOZ_OVERRIDE;
     virtual bool objectClassIs(HandleObject obj, js::ESClassValue classValue, JSContext *cx) MOZ_OVERRIDE;
     virtual const char* className(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE;
-    virtual bool preventExtensions(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE;
-    virtual bool isExtensible(JSContext *cx, HandleObject proxy, bool *extensible) MOZ_OVERRIDE;
+    virtual void finalize(JSFreeOp *fop, JSObject *proxy) MOZ_OVERRIDE;
 
     static CPOWProxyHandler singleton;
 };
 
 CPOWProxyHandler CPOWProxyHandler::singleton;
 
 bool
+CPOWProxyHandler::preventExtensions(JSContext *cx, HandleObject proxy)
+{
+    return ParentOf(proxy)->preventExtensions(cx, proxy);
+}
+
+bool
+JavaScriptParent::preventExtensions(JSContext *cx, HandleObject proxy)
+{
+    ObjectId objId = idOf(proxy);
+
+    ReturnStatus status;
+    if (!CallPreventExtensions(objId, &status))
+        return ipcfail(cx);
+
+    return ok(cx, status);
+}
+
+bool
 CPOWProxyHandler::getPropertyDescriptor(JSContext *cx, HandleObject proxy, HandleId id,
                                         PropertyDescriptor *desc, unsigned flags)
 {
     return ParentOf(proxy)->getPropertyDescriptor(cx, proxy, id, desc, flags);
 }
 
 bool
 JavaScriptParent::getPropertyDescriptor(JSContext *cx, HandleObject proxy, HandleId id,
@@ -181,40 +199,16 @@ CPOWProxyHandler::getOwnPropertyNames(JS
 
 bool
 JavaScriptParent::getOwnPropertyNames(JSContext *cx, HandleObject proxy, AutoIdVector &props)
 {
     return getPropertyNames(cx, proxy, JSITER_OWNONLY | JSITER_HIDDEN, props);
 }
 
 bool
-CPOWProxyHandler::keys(JSContext *cx, HandleObject proxy, AutoIdVector &props)
-{
-    return ParentOf(proxy)->keys(cx, proxy, props);
-}
-
-bool
-JavaScriptParent::keys(JSContext *cx, HandleObject proxy, AutoIdVector &props)
-{
-    return getPropertyNames(cx, proxy, JSITER_OWNONLY, props);
-}
-
-bool
-CPOWProxyHandler::enumerate(JSContext *cx, HandleObject proxy, AutoIdVector &props)
-{
-    return ParentOf(proxy)->enumerate(cx, proxy, props);
-}
-
-bool
-JavaScriptParent::enumerate(JSContext *cx, HandleObject proxy, AutoIdVector &props)
-{
-    return getPropertyNames(cx, proxy, 0, props);
-}
-
-bool
 CPOWProxyHandler::delete_(JSContext *cx, HandleObject proxy, HandleId id, bool *bp)
 {
     return ParentOf(proxy)->delete_(cx, proxy, id, bp);
 }
 
 bool
 JavaScriptParent::delete_(JSContext *cx, HandleObject proxy, HandleId id, bool *bp)
 {
@@ -227,49 +221,25 @@ JavaScriptParent::delete_(JSContext *cx,
     ReturnStatus status;
     if (!CallDelete(objId, idstr, &status, bp))
         return ipcfail(cx);
 
     return ok(cx, status);
 }
 
 bool
-CPOWProxyHandler::preventExtensions(JSContext *cx, HandleObject proxy)
+CPOWProxyHandler::enumerate(JSContext *cx, HandleObject proxy, AutoIdVector &props)
 {
-    return ParentOf(proxy)->preventExtensions(cx, proxy);
+    return ParentOf(proxy)->enumerate(cx, proxy, props);
 }
 
 bool
-JavaScriptParent::preventExtensions(JSContext *cx, HandleObject proxy)
-{
-    ObjectId objId = idOf(proxy);
-
-    ReturnStatus status;
-    if (!CallPreventExtensions(objId, &status))
-        return ipcfail(cx);
-
-    return ok(cx, status);
-}
-
-bool
-CPOWProxyHandler::isExtensible(JSContext *cx, HandleObject proxy, bool *extensible)
+JavaScriptParent::enumerate(JSContext *cx, HandleObject proxy, AutoIdVector &props)
 {
-    return ParentOf(proxy)->isExtensible(cx, proxy, extensible);
-}
-
-bool
-JavaScriptParent::isExtensible(JSContext *cx, HandleObject proxy, bool *extensible)
-{
-    ObjectId objId = idOf(proxy);
-
-    ReturnStatus status;
-    if (!CallIsExtensible(objId, &status, extensible))
-        return ipcfail(cx);
-
-    return ok(cx, status);
+    return getPropertyNames(cx, proxy, 0, props);
 }
 
 bool
 CPOWProxyHandler::has(JSContext *cx, HandleObject proxy, HandleId id, bool *bp)
 {
     return ParentOf(proxy)->has(cx, proxy, id, bp);
 }
 
@@ -369,16 +339,46 @@ JavaScriptParent::set(JSContext *cx, JS:
 
     if (!ok(cx, status))
         return false;
 
     return toValue(cx, result, vp);
 }
 
 bool
+CPOWProxyHandler::keys(JSContext *cx, HandleObject proxy, AutoIdVector &props)
+{
+    return ParentOf(proxy)->keys(cx, proxy, props);
+}
+
+bool
+JavaScriptParent::keys(JSContext *cx, HandleObject proxy, AutoIdVector &props)
+{
+    return getPropertyNames(cx, proxy, JSITER_OWNONLY, props);
+}
+
+bool
+CPOWProxyHandler::isExtensible(JSContext *cx, HandleObject proxy, bool *extensible)
+{
+    return ParentOf(proxy)->isExtensible(cx, proxy, extensible);
+}
+
+bool
+JavaScriptParent::isExtensible(JSContext *cx, HandleObject proxy, bool *extensible)
+{
+    ObjectId objId = idOf(proxy);
+
+    ReturnStatus status;
+    if (!CallIsExtensible(objId, &status, extensible))
+        return ipcfail(cx);
+
+    return ok(cx, status);
+}
+
+bool
 CPOWProxyHandler::call(JSContext *cx, HandleObject proxy, const CallArgs &args)
 {
     return ParentOf(proxy)->call(cx, proxy, args);
 }
 
 bool
 JavaScriptParent::call(JSContext *cx, HandleObject proxy, const CallArgs &args)
 {
@@ -441,35 +441,16 @@ JavaScriptParent::call(JSContext *cx, Ha
     }
 
     if (!toValue(cx, result, args.rval()))
         return false;
 
     return true;
 }
 
-void
-CPOWProxyHandler::finalize(JSFreeOp *fop, JSObject *proxy)
-{
-    ParentOf(proxy)->drop(proxy);
-}
-
-void
-JavaScriptParent::drop(JSObject *obj)
-{
-    if (inactive_)
-        return;
-
-    ObjectId objId = idOf(obj);
-
-    objects_.remove(objId);
-    if (!SendDropObject(objId))
-        MOZ_CRASH();
-    decref();
-}
 
 bool
 CPOWProxyHandler::objectClassIs(HandleObject proxy, js::ESClassValue classValue, JSContext *cx)
 {
     return ParentOf(proxy)->objectClassIs(cx, proxy, classValue);
 }
 
 bool
@@ -499,16 +480,36 @@ JavaScriptParent::className(JSContext *c
 
     nsString name;
     if (!CallClassName(objId, &name))
         return NULL;
 
     return ToNewCString(name);
 }
 
+void
+CPOWProxyHandler::finalize(JSFreeOp *fop, JSObject *proxy)
+{
+    ParentOf(proxy)->drop(proxy);
+}
+
+void
+JavaScriptParent::drop(JSObject *obj)
+{
+    if (inactive_)
+        return;
+
+    ObjectId objId = idOf(obj);
+
+    objects_.remove(objId);
+    if (!SendDropObject(objId))
+        MOZ_CRASH();
+    decref();
+}
+
 bool
 JavaScriptParent::init()
 {
     if (!JavaScriptShared::init())
         return false;
 
     return true;
 }

--- a/js/ipc/JavaScriptParent.h
+++ b/js/ipc/JavaScriptParent.h
@@ -25,37 +25,44 @@ class JavaScriptParent
     public JavaScriptShared
 {
   public:
     JavaScriptParent();
 
     bool init();
 
   public:
-    bool has(JSContext *cx, JS::HandleObject proxy, JS::HandleId id, bool *bp);
-    bool hasOwn(JSContext *cx, JS::HandleObject proxy, JS::HandleId id, bool *bp);
-    bool get(JSContext *cx, JS::HandleObject proxy, JS::HandleObject receiver,
-             JS::HandleId id, JS::MutableHandleValue vp);
-    bool set(JSContext *cx, JS::HandleObject proxy, JS::HandleObject receiver,
-             JS::HandleId id, bool strict, JS::MutableHandleValue vp);
-    bool call(JSContext *cx, JS::HandleObject proxy, const JS::CallArgs &args);
+    // Fundamental proxy traps. These are required.
+    // (The traps should be in the same order like js/src/jsproxy.h)
+    bool preventExtensions(JSContext *cx, JS::HandleObject proxy);
     bool getPropertyDescriptor(JSContext *cx, JS::HandleObject proxy, JS::HandleId id,
                                JSPropertyDescriptor *desc, unsigned flags);
     bool getOwnPropertyDescriptor(JSContext *cx, JS::HandleObject proxy, JS::HandleId id,
                                   JSPropertyDescriptor *desc, unsigned flags);
     bool defineProperty(JSContext *cx, JS::HandleObject proxy, JS::HandleId id,
                         JSPropertyDescriptor *desc);
     bool getOwnPropertyNames(JSContext *cx, JS::HandleObject proxy, js::AutoIdVector &props);
-    bool keys(JSContext *cx, JS::HandleObject proxy, js::AutoIdVector &props);
+    bool delete_(JSContext *cx, JS::HandleObject proxy, JS::HandleId id, bool *bp);
     bool enumerate(JSContext *cx, JS::HandleObject proxy, js::AutoIdVector &props);
-    bool delete_(JSContext *cx, JS::HandleObject proxy, JS::HandleId id, bool *bp);
+
+    // Derived proxy traps. Implementing these is useful for perfomance.
+    bool has(JSContext *cx, JS::HandleObject proxy, JS::HandleId id, bool *bp);
+    bool hasOwn(JSContext *cx, JS::HandleObject proxy, JS::HandleId id, bool *bp);
+    bool get(JSContext *cx, JS::HandleObject proxy, JS::HandleObject receiver,
+             JS::HandleId id, JS::MutableHandleValue vp);
+    bool set(JSContext *cx, JS::HandleObject proxy, JS::HandleObject receiver,
+             JS::HandleId id, bool strict, JS::MutableHandleValue vp);
+    bool keys(JSContext *cx, JS::HandleObject proxy, js::AutoIdVector &props);
+    // We use "iterate" provided by the base class here.
+
+    // SpiderMonkey Extensions.
+    bool isExtensible(JSContext *cx, JS::HandleObject proxy, bool *extensible);
+    bool call(JSContext *cx, JS::HandleObject proxy, const JS::CallArgs &args);
     bool objectClassIs(JSContext *cx, JS::HandleObject obj, js::ESClassValue classValue);
     const char* className(JSContext *cx, JS::HandleObject proxy);
-    bool preventExtensions(JSContext *cx, JS::HandleObject proxy);
-    bool isExtensible(JSContext *cx, JS::HandleObject proxy, bool *extensible);
 
     void decref();
     void incref();
     void destroyFromContent();
 
     void drop(JSObject *obj);
 
     static bool IsCPOW(JSObject *obj);

--- a/js/ipc/PJavaScript.ipdl
+++ b/js/ipc/PJavaScript.ipdl
@@ -18,31 +18,33 @@ rpc protocol PJavaScript
 {
     manager PContent;
 
 child:
     // The parent process no longer holds any references to the child object.
     async DropObject(uint64_t objId);
 
     // These roughly map to the ProxyHandler hooks that CPOWs need.
+    urgent PreventExtensions(uint64_t objId) returns (ReturnStatus rs);
+    urgent GetPropertyDescriptor(uint64_t objId, nsString id, uint32_t flags) returns (ReturnStatus rs, PPropertyDescriptor result);
+    urgent GetOwnPropertyDescriptor(uint64_t objId, nsString id, uint32_t flags) returns (ReturnStatus rs, PPropertyDescriptor result);
+    urgent DefineProperty(uint64_t objId, nsString id, PPropertyDescriptor descriptor) returns (ReturnStatus rs);
+    urgent Delete(uint64_t objId, nsString id) returns (ReturnStatus rs, bool successful);
+
     urgent Has(uint64_t objId, nsString id) returns (ReturnStatus rs, bool has);
     urgent HasOwn(uint64_t objId, nsString id) returns (ReturnStatus rs, bool has);
     urgent Get(uint64_t objId, uint64_t receiverId, nsString id) returns (ReturnStatus rs, JSVariant result);
     urgent Set(uint64_t objId, uint64_t receiverId, nsString id, bool strict, JSVariant value) returns (ReturnStatus rs, JSVariant result);
+
+    urgent IsExtensible(uint64_t objId) returns (ReturnStatus rs, bool result);
     urgent Call(uint64_t objId, JSParam[] argv) returns (ReturnStatus rs, JSVariant result, JSParam[] outparams);
-
-    urgent InstanceOf(uint64_t objId, JSIID iid) returns (ReturnStatus rs, bool instanceof);
-    urgent GetPropertyDescriptor(uint64_t objId, nsString id, uint32_t flags) returns (ReturnStatus rs, PPropertyDescriptor result);
-    urgent GetOwnPropertyDescriptor(uint64_t objId, nsString id, uint32_t flags) returns (ReturnStatus rs, PPropertyDescriptor result);
-    urgent DefineProperty(uint64_t objId, nsString id, PPropertyDescriptor descriptor) returns (ReturnStatus rs);
-    urgent GetPropertyNames(uint64_t objId, uint32_t flags) returns (ReturnStatus rs, nsString[] names);
     urgent ObjectClassIs(uint64_t objId, uint32_t classValue) returns (bool result);
     urgent ClassName(uint64_t objId) returns (nsString name);
-    urgent IsExtensible(uint64_t objId) returns (ReturnStatus rs, bool result);
-    urgent PreventExtensions(uint64_t objId) returns (ReturnStatus rs);
-    urgent Delete(uint64_t objId, nsString id) returns (ReturnStatus rs, bool successful);
+
+    urgent GetPropertyNames(uint64_t objId, uint32_t flags) returns (ReturnStatus rs, nsString[] names);
+    urgent InstanceOf(uint64_t objId, JSIID iid) returns (ReturnStatus rs, bool instanceof);
 
 parent:
     async __delete__();
 };
 
 }
 }