Introduce Object::DebugGetProperty.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 96c397f51bd22331614248c1baf9203316c6fbd7..5fb6e9045470b18360c543fde8f158e8efd91ed7 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -1081,6 +1081,48 @@ bool Object::HasSpecificClassOf(String* name) {
 }
 
 
+MaybeHandle<Object> JSObject::GetPropertyAfterAccessCheck(
+    Isolate* isolate,
+    Handle<Object> receiver,
+    Handle<Name> name,
+    LookupResult* result,
+    PropertyAttributes* attributes) {
+  Handle<Object> value;
+  switch (result->type()) {
+    case NORMAL: {
+      value = JSObject::GetNormalizedProperty(
+          handle(result->holder(), isolate), result);
+      break;
+    }
+    case FIELD:
+      value = JSObject::FastPropertyAt(handle(result->holder(), isolate),
+                                       result->representation(),
+                                       result->GetFieldIndex().field_index());
+      break;
+    case CONSTANT:
+      return handle(result->GetConstant(), isolate);
+    case CALLBACKS:
+      return JSObject::GetPropertyWithCallback(
+          handle(result->holder(), isolate),
+          receiver,
+          handle(result->GetCallbackObject(), isolate),
+          name);
+    case HANDLER:
+      return JSProxy::GetPropertyWithHandler(
+          handle(result->proxy(), isolate), receiver, name);
+    case INTERCEPTOR:
+      return JSObject::GetPropertyWithInterceptor(
+          handle(result->holder(), isolate), receiver, name, attributes);
+    case NONEXISTENT:
+      UNREACHABLE();
+      break;
+  }
+  ASSERT(!value->IsTheHole() || result->IsReadOnly());
+  return value->IsTheHole()
+      ? Handle<Object>::cast(isolate->factory()->undefined_value()) : value;
+}
+
+
 MaybeHandle<Object> Object::GetProperty(Handle<Object> object,
                                         Handle<Name> name) {
   PropertyAttributes attributes;