Make Object.freeze/seal/preventExtensions observable

test/mjsunit/harmony/object-observe.js

Index: test/mjsunit/harmony/object-observe.js
diff --git a/test/mjsunit/harmony/object-observe.js b/test/mjsunit/harmony/object-observe.js
index f94ab75e9a84d2cf0d819510782b23a660057bcc..d190016ca79c46e2da96f8fb7a140bea9047561b 100644
--- a/test/mjsunit/harmony/object-observe.js
+++ b/test/mjsunit/harmony/object-observe.js
@@ -300,8 +300,79 @@ observer.assertCallbackRecords([
   { object: obj, type: 'deleted', name: '', oldValue: ' ' },
 ]);
 
+// Object.preventExtensions

[rossberg, 2013/10/30 19:11:45]

Cases you could add:

- invoking preventExtensions/seal/freeze on an object that already has
preventExtensions (should not create a preventExtensions change record)

- invoking seal/freeze on an object where not all properties can be
sealed/frozen (should still generate a preventExtensions change record, IIRC)

[rafaelw, 2013/10/30 23:00:30]

Good catch. Note that we now exit early from JSObject::PreventExtensions if the
map is already marked non-extensible.
I can't think of how to generate this case. How can this arise?

[rossberg, 2013/10/31 08:03:20]

Can you add a similar test for seal and freeze?
I'm sorry, you are right, it can't -- I keep forgetting that JavaScript has this
crank semantics where you can still change a data property from writable to
non-writable, even if it's allegedly non-configurable. 8/

[rafaelw, 2013/11/05 12:20:31]

Done.

+reset();
+var obj = { foo: 'bar'};
+Object.observe(obj, observer.callback);
+obj.baz = 'bat';
+Object.preventExtensions(obj);
+
+Object.deliverChangeRecords(observer.callback);
+observer.assertCallbackRecords([
+  { object: obj, type: 'new', name: 'baz' },
+  { object: obj, type: 'preventExtensions' },
+]);
+
+// Object.freeze
+reset();
+var obj = { a: 'a' };
+Object.defineProperty(obj, 'b', {
+  writable: false,
+  configurable: true,
+  value: 'b'
+});
+Object.defineProperty(obj, 'c', {
+  writable: true,
+  configurable: false,
+  value: 'c'
+});
+Object.defineProperty(obj, 'd', {
+  writable: false,
+  configurable: false,
+  value: 'd'
+});
+Object.observe(obj, observer.callback);
+Object.freeze(obj);
+
+Object.deliverChangeRecords(observer.callback);
+observer.assertCallbackRecords([
+  { object: obj, type: 'reconfigured', name: 'a' },
+  { object: obj, type: 'reconfigured', name: 'b' },
+  { object: obj, type: 'reconfigured', name: 'c' },
+  { object: obj, type: 'preventExtensions' },
+]);
+
+// Object.seal
+reset();
+var obj = { a: 'a' };
+Object.defineProperty(obj, 'b', {
+  writable: false,
+  configurable: true,
+  value: 'b'
+});
+Object.defineProperty(obj, 'c', {
+  writable: true,
+  configurable: false,
+  value: 'c'
+});
+Object.defineProperty(obj, 'd', {
+  writable: false,
+  configurable: false,
+  value: 'd'
+});
+Object.observe(obj, observer.callback);
+Object.seal(obj);
+
+Object.deliverChangeRecords(observer.callback);
+observer.assertCallbackRecords([
+  { object: obj, type: 'reconfigured', name: 'a' },
+  { object: obj, type: 'reconfigured', name: 'b' },
+  { object: obj, type: 'preventExtensions' },
+]);
+
 // Observing a continuous stream of changes, while itermittantly unobserving.
 reset();
+var obj = {};
 Object.observe(obj, observer.callback);
 Object.getNotifier(obj).notify({
   type: 'updated',