Object.observe: don't unnecessarily emit oldValue for reconfigurations of data properties

test/mjsunit/harmony/object-observe.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 353 matching lines @@
 delete obj.a;
 Object.defineProperty(obj, "a", {value: 11, configurable: true});
 Object.deliverChangeRecords(observer.callback);
 observer.assertCallbackRecords([
   { object: obj, name: "a", type: "updated", oldValue: 1 },
   { object: obj, name: "a", type: "updated", oldValue: 2 },
   { object: obj, name: "a", type: "deleted", oldValue: 3 },
   { object: obj, name: "a", type: "new" },
   { object: obj, name: "a", type: "updated", oldValue: 4 },
   { object: obj, name: "a", type: "updated", oldValue: 5 },
-  { object: obj, name: "a", type: "reconfigured", oldValue: 6 },
+  { object: obj, name: "a", type: "reconfigured" },
   { object: obj, name: "a", type: "updated", oldValue: 6 },
   { object: obj, name: "a", type: "reconfigured", oldValue: 8 },
   { object: obj, name: "a", type: "reconfigured", oldValue: 7 },
   { object: obj, name: "a", type: "reconfigured" },
   { object: obj, name: "a", type: "reconfigured" },
   { object: obj, name: "a", type: "reconfigured" },
   { object: obj, name: "a", type: "deleted" },
   { object: obj, name: "a", type: "new" },
   { object: obj, name: "a", type: "reconfigured" },
   { object: obj, name: "a", type: "updated", oldValue: 9 },
@@ skipping 37 matching lines @@
 delete obj[1];
 Object.defineProperty(obj, "1", {value: 11, configurable: true});
 Object.deliverChangeRecords(observer.callback);
 observer.assertCallbackRecords([
   { object: obj, name: "1", type: "updated", oldValue: 1 },
   { object: obj, name: "1", type: "updated", oldValue: 2 },
   { object: obj, name: "1", type: "deleted", oldValue: 3 },
   { object: obj, name: "1", type: "new" },
   { object: obj, name: "1", type: "updated", oldValue: 4 },
   { object: obj, name: "1", type: "updated", oldValue: 5 },
-  { object: obj, name: "1", type: "reconfigured", oldValue: 6 },
+  { object: obj, name: "1", type: "reconfigured" },
   { object: obj, name: "1", type: "updated", oldValue: 6 },
   { object: obj, name: "1", type: "reconfigured", oldValue: 8 },
   { object: obj, name: "1", type: "reconfigured", oldValue: 7 },
   { object: obj, name: "1", type: "reconfigured" },
   { object: obj, name: "1", type: "reconfigured" },
   { object: obj, name: "1", type: "reconfigured" },
   { object: obj, name: "1", type: "deleted" },
   { object: obj, name: "1", type: "new" },
   { object: obj, name: "1", type: "reconfigured" },
   { object: obj, name: "1", type: "updated", oldValue: 9 },
@@ skipping 43 matching lines @@
   delete obj[prop];
   Object.defineProperty(obj, prop, {value: 11, configurable: true});
   Object.deliverChangeRecords(observer.callback);
   observer.assertCallbackRecords([
     { object: obj, name: prop, type: "updated", oldValue: 1 },
     { object: obj, name: prop, type: "updated", oldValue: 2 },
     { object: obj, name: prop, type: "deleted", oldValue: 3 },
     { object: obj, name: prop, type: "new" },
     { object: obj, name: prop, type: "updated", oldValue: 4 },
     { object: obj, name: prop, type: "updated", oldValue: 5 },
-    { object: obj, name: prop, type: "reconfigured", oldValue: 6 },
+    { object: obj, name: prop, type: "reconfigured" },
     { object: obj, name: prop, type: "updated", oldValue: 6 },
     { object: obj, name: prop, type: "reconfigured", oldValue: 8 },
     { object: obj, name: prop, type: "reconfigured", oldValue: 7 },
     { object: obj, name: prop, type: "reconfigured" },
     { object: obj, name: prop, type: "reconfigured" },
     { object: obj, name: prop, type: "reconfigured" },
     { object: obj, name: prop, type: "reconfigured" },
     { object: obj, name: prop, type: "reconfigured" },
     { object: obj, name: prop, type: "deleted" },
     { object: obj, name: prop, type: "new" },
@@ skipping 23 matching lines @@
   Object.defineProperty(obj, prop, {value: 7});
   Object.defineProperty(obj, prop, {enumerable: desc.enumerable});  // ignored
   Object.defineProperty(obj, prop, {writable: false});
   obj[prop] = 7;  // ignored
   Object.deliverChangeRecords(observer.callback);
   observer.assertCallbackRecords([
     { object: obj, name: prop, type: "updated", oldValue: 1 },
     { object: obj, name: prop, type: "updated", oldValue: 4 },
     { object: obj, name: prop, type: "updated", oldValue: 5 },
     { object: obj, name: prop, type: "updated", oldValue: 6 },
-    { object: obj, name: prop, type: "reconfigured", oldValue: 7 },
+    { object: obj, name: prop, type: "reconfigured" },
   ]);
   Object.unobserve(obj, observer.callback);
 }
 
 function createProxy(create, x) {
   var handler = {
     getPropertyDescriptor: function(k) {
       for (var o = this.target; o; o = Object.getPrototypeOf(o)) {
         var desc = Object.getOwnPropertyDescriptor(o, k);
         if (desc) return desc;
@@ skipping 99 matching lines @@
 Object.defineProperty(arr3, 'length', {value: 5});
 Object.defineProperty(arr3, 'length', {value: 10, writable: false});
 Object.deliverChangeRecords(observer.callback);
 observer.assertCallbackRecords([
   { object: arr, name: '3', type: 'deleted', oldValue: 'd' },
   { object: arr, name: '2', type: 'deleted' },
   { object: arr, name: 'length', type: 'updated', oldValue: 4 },
   { object: arr, name: '1', type: 'deleted', oldValue: 'b' },
   { object: arr, name: 'length', type: 'updated', oldValue: 2 },
   { object: arr, name: 'length', type: 'updated', oldValue: 1 },
-  { object: arr, name: 'length', type: 'reconfigured', oldValue: 10 },
+  { object: arr, name: 'length', type: 'reconfigured' },
   { object: arr2, name: '1', type: 'deleted', oldValue: 'beta' },
   { object: arr2, name: 'length', type: 'updated', oldValue: 2 },
   { object: arr2, name: 'length', type: 'reconfigured', oldValue: 1 },
   { object: arr3, name: '2', type: 'deleted', oldValue: 'goodbye' },
   { object: arr3, name: '0', type: 'deleted', oldValue: 'hello' },
   { object: arr3, name: 'length', type: 'updated', oldValue: 6 },
   { object: arr3, name: 'length', type: 'updated', oldValue: 0 },
   { object: arr3, name: 'length', type: 'updated', oldValue: 1 },
   { object: arr3, name: 'length', type: 'updated', oldValue: 2 },
   { object: arr3, name: 'length', type: 'updated', oldValue: 1 },
@@ skipping 374 matching lines @@
     for (var n1 = 0; n1 < 3; ++n1)
       for (var n2 = 0; n2 < 3; ++n2)
         for (var i in mutation)
           TestFastElementsLength(mutation[i], b1 != 0, b2 != 0, 20*n1, 20*n2);
 
 for (var b1 = 0; b1 < 2; ++b1)
   for (var b2 = 0; b2 < 2; ++b2)
     for (var n = 0; n < 3; ++n)
       for (var i in mutationByIncr)
         TestFastElementsLength(mutationByIncr[i], b1 != 0, b2 != 0, 7*n, 7*n+1);