Re-enable Object.observe and add enforcement for security invariants.

test/mjsunit/es7/object-observe.js

Index: test/mjsunit/es7/object-observe.js
diff --git a/test/mjsunit/es7/object-observe.js b/test/mjsunit/es7/object-observe.js
index 0aa3601d73bddd93769d38f256a7798363265c5d..8ec22bceba701c6841ff7657de9dacee2168201f 100644
--- a/test/mjsunit/es7/object-observe.js
+++ b/test/mjsunit/es7/object-observe.js
@@ -113,6 +113,8 @@ Object.defineProperty(changeRecordWithAccessor, 'name', {
 // Object.observe
 assertThrows(function() { Object.observe("non-object", observer.callback); },
              TypeError);
+assertThrows(function() { Object.observe(this, observer.callback); },
+             TypeError);
 assertThrows(function() { Object.observe(obj, nonFunction); }, TypeError);
 assertThrows(function() { Object.observe(obj, frozenFunction); }, TypeError);
 assertEquals(obj, Object.observe(obj, observer.callback, [1]));
@@ -127,6 +129,8 @@ assertEquals(obj, Object.observe(obj, observer.callback));
 
 // Object.unobserve
 assertThrows(function() { Object.unobserve(4, observer.callback); }, TypeError);
+assertThrows(function() { Object.unobserve(this, observer.callback); },
+             TypeError);
 assertThrows(function() { Object.unobserve(obj, nonFunction); }, TypeError);
 assertEquals(obj, Object.unobserve(obj, observer.callback));
 
@@ -135,6 +139,7 @@ assertEquals(obj, Object.unobserve(obj, observer.callback));
 var notifier = Object.getNotifier(obj);
 assertSame(notifier, Object.getNotifier(obj));
 assertEquals(null, Object.getNotifier(Object.freeze({})));
+assertThrows(function() { Object.getNotifier(this) }, TypeError);
 assertFalse(notifier.hasOwnProperty('notify'));
 assertEquals([], Object.keys(notifier));
 var notifyDesc = Object.getOwnPropertyDescriptor(notifier.__proto__, 'notify');
@@ -1074,6 +1079,8 @@ function TestObserveNonConfigurable(obj, prop, desc) {
   Object.unobserve(obj, observer.callback);
 }
 
+// TODO(rafaelw) Enable when ES6 Proxies are implemented
+/*
 function createProxy(create, x) {
   var handler = {
     getPropertyDescriptor: function(k) {
@@ -1113,11 +1120,11 @@ function createProxy(create, x) {
   Object.observe(handler.target, handler.callback);
   return handler.proxy = create(handler, x);
 }
+*/
 
 var objects = [
   {},
   [],
-  this,  // global object
   function(){},
   (function(){ return arguments })(),
   (function(){ "use strict"; return arguments })(),
@@ -1125,9 +1132,10 @@ var objects = [
   new Date(),
   Object, Function, Date, RegExp,
   new Set, new Map, new WeakMap,
-  new ArrayBuffer(10), new Int32Array(5),
-  createProxy(Proxy.create, null),
-  createProxy(Proxy.createFunction, function(){}),
+  new ArrayBuffer(10), new Int32Array(5)
+// TODO(rafaelw) Enable when ES6 Proxies are implemented.
+//  createProxy(Proxy.create, null),
+//  createProxy(Proxy.createFunction, function(){}),
 ];
 var properties = ["a", "1", 1, "length", "setPrototype", "name", "caller"];