Bug 858101 - Run the DefaultValue algorithm directly on the wrapper for Xrays. r=mrbkap

js/src/jsfriendapi.h

@@ -1717,6 +1717,11 @@ SetObjectMetadata(JSContext *cx, JSHandleObject obj, JSHandleObject metadata);
 JS_FRIEND_API(JSObject *)
 GetObjectMetadata(JSObject *obj);
 
+/* ES5 8.12.8. */
+extern JS_FRIEND_API(JSBool)
+DefaultValue(JSContext *cx, HandleObject obj, JSType hint, MutableHandleValue vp);
+
+
 } /* namespace js */
 
 extern JS_FRIEND_API(JSBool)

js/src/jsobj.cpp

@@ -4609,7 +4609,7 @@ MaybeCallMethod(JSContext *cx, HandleObject obj, HandleId id, MutableHandleValue
     return Invoke(cx, ObjectValue(*obj), vp, 0, NULL, vp.address());
 }
 
-JSBool
+JS_FRIEND_API(JSBool)
 js::DefaultValue(JSContext *cx, HandleObject obj, JSType hint, MutableHandleValue vp)
 {
     JS_ASSERT(hint == JSTYPE_NUMBER || hint == JSTYPE_STRING || hint == JSTYPE_VOID);

js/src/jsobj.h

@@ -203,10 +203,6 @@ DeleteGeneric(JSContext *cx, HandleObject obj, HandleId id, JSBool *succeeded);
 
 } /* namespace js::baseops */
 
-/* ES5 8.12.8. */
-extern JSBool
-DefaultValue(JSContext *cx, HandleObject obj, JSType hint, MutableHandleValue vp);
-
 extern Class ArrayClass;
 extern Class ArrayBufferClass;
 extern Class BlockClass;

js/xpconnect/wrappers/XrayWrapper.cpp

@@ -1885,6 +1885,20 @@ XrayWrapper<Base, Traits>::construct(JSContext *cx, HandleObject wrapper, const
     return Traits::construct(cx, wrapper, args, Base::singleton);
 }
 
+template <typename Base, typename Traits>
+bool
+XrayWrapper<Base, Traits>::defaultValue(JSContext *cx, HandleObject wrapper,
+                                        JSType hint, MutableHandleValue vp)
+{
+    // Even if this isn't a security wrapper, Xray semantics dictate that we
+    // run the DefaultValue algorithm directly on the Xray wrapper.
+    //
+    // NB: We don't have to worry about things with special [[DefaultValue]]
+    // behavior like Date because we'll never have an XrayWrapper to them.
+    return js::DefaultValue(cx, wrapper, hint, vp);
+}
+
+
 /*
  * The Permissive / Security variants should be used depending on whether the
  * compartment of the wrapper is guranteed to subsume the compartment of the

js/xpconnect/wrappers/XrayWrapper.h

@@ -103,6 +103,10 @@ class XrayWrapper : public Base {
     virtual bool construct(JSContext *cx, JS::Handle<JSObject*> wrapper,
                            const JS::CallArgs &args) MOZ_OVERRIDE;
 
+    virtual bool defaultValue(JSContext *cx, JS::HandleObject wrapper,
+                              JSType hint, JS::MutableHandleValue vp)
+                              MOZ_OVERRIDE;
+
     static XrayWrapper singleton;
 
   private: