[builtins] introduce AsyncBuiltinsAssembler for ES2016 features and beyond

src/builtins/builtins-promise.h

Index: src/builtins/builtins-promise.h
diff --git a/src/builtins/builtins-promise.h b/src/builtins/builtins-promise.h
index dee9a075a27969a0ff8a5bdb92da61014d24cd3d..c56ba18773523dab930d15295db04671d2a3c642 100644
--- a/src/builtins/builtins-promise.h
+++ b/src/builtins/builtins-promise.h
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifndef V8_BUILTINS_BUILTINS_PROMISE_H_
+#define V8_BUILTINS_BUILTINS_PROMISE_H_
+
 #include "src/code-stub-assembler.h"
 #include "src/contexts.h"
 
@@ -118,3 +121,5 @@ class PromiseBuiltinsAssembler : public CodeStubAssembler {
 
 }  // namespace internal
 }  // namespace v8
+
+#endif  // V8_BUILTINS_BUILTINS_PROMISE_H_