Use instance type in Object::IsErrorObject().

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 662 matching lines @@
   return map()->instance_type() >= FIRST_JS_RECEIVER_TYPE;
 }
 
 bool HeapObject::IsJSObject() const {
   STATIC_ASSERT(LAST_JS_OBJECT_TYPE == LAST_TYPE);
   return map()->IsJSObjectMap();
 }
 
 bool HeapObject::IsJSProxy() const { return map()->IsJSProxyMap(); }
 
+bool HeapObject::IsJSError() const {
+  return map()->instance_type() == JS_ERROR_TYPE;
+}
+
 TYPE_CHECKER(JSSet, JS_SET_TYPE)
 TYPE_CHECKER(JSMap, JS_MAP_TYPE)
 TYPE_CHECKER(JSSetIterator, JS_SET_ITERATOR_TYPE)
 TYPE_CHECKER(JSMapIterator, JS_MAP_ITERATOR_TYPE)
 TYPE_CHECKER(JSWeakMap, JS_WEAK_MAP_TYPE)
 TYPE_CHECKER(JSWeakSet, JS_WEAK_SET_TYPE)
 TYPE_CHECKER(JSContextExtensionObject, JS_CONTEXT_EXTENSION_OBJECT_TYPE)
 TYPE_CHECKER(Map, MAP_TYPE)
 TYPE_CHECKER(FixedDoubleArray, FIXED_DOUBLE_ARRAY_TYPE)
 TYPE_CHECKER(WeakFixedArray, FIXED_ARRAY_TYPE)
@@ skipping 7241 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_