Add API for access checks on observed objects

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 70f0d3628f01b1f109f546e85253d04bcb1c8f10..6a660174cf578bd8483f9371e28a124897b68947 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -13541,6 +13541,23 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectHashTableSet) {
 }
 
 
+RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectObserveAllowed) {
+  ASSERT(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSReceiver, receiver, 0);
+  // Proxies aren't currently allowed to have access checks enabled
+  if (receiver->IsJSProxy()) return isolate->heap()->true_value();
+  JSObject* object = JSObject::cast(receiver);
+  if (object->IsJSGlobalProxy()) {
+    Object* proto = object->GetPrototype();
+    if (proto->IsNull()) return isolate->heap()->false_value();
+    ASSERT(proto->IsJSGlobalObject());
+    object = JSObject::cast(proto);
+  }
+  if (!object->IsAccessCheckNeeded()) return isolate->heap()->true_value();
+  return isolate->heap()->ToBoolean(isolate->MayObserveAccess(object));
+}
+
+
 // ----------------------------------------------------------------------------
 // Implementation of Runtime