Add GetPropertyAttribute method for Object in the API

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 1157d723701648c2ee2d05c908c4b338722bbeaa..9843caad8dcb4ce8fd275ff9dac3785bafb36b95 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -2601,6 +2601,36 @@ PropertyAttributes JSReceiver::GetPropertyAttribute(JSReceiver* receiver,
 }
 
 
+PropertyAttributes JSReceiver::TryGetPropertyAttribute(
+    Handle<Object> key,
+    bool* has_pending_exception) {
+  Isolate* isolate = GetHeap()->isolate();
+  HandleScope scope(isolate);
+
+  Handle<String> name;
+  if (key->IsString()) {
+    name = Handle<String>::cast(key);
+  } else {
+    bool has_pending_exception = false;
+    Handle<Object> converted =
+        Execution::ToString(key, &has_pending_exception);
+    if (has_pending_exception) return ABSENT;
+    name = Handle<String>::cast(converted);
+  }
+  PropertyAttributes attr = GetPropertyAttributeWithReceiver(this, *name);
+
+  // Throws an exception when the property doesn't exist.

[Mads Ager (chromium), 2011/07/15 07:25:51]

Let's just return NONE in that case and document that behavior? Then the user
can use a combination of Has and GetPropertyAttributes if he doesn't know if the
property exists?

+  if (attr == ABSENT) {
+    i::Handle<i::Object> error_obj = isolate->factory()->NewReferenceError(
+        "not_defined", i::HandleVector(&name, 1));
+    isolate->Throw(*error_obj);
+    *has_pending_exception = true;
+  }
+
+  return attr;
+}
+
+
 PropertyAttributes JSReceiver::GetLocalPropertyAttribute(String* name) {
   // Check whether the name is an array index.
   uint32_t index = 0;