[builtins] FastNewClosureStub becomes a builtin.

src/builtins/builtins-constructor.h

Index: src/builtins/builtins-constructor.h
diff --git a/src/builtins/builtins-constructor.h b/src/builtins/builtins-constructor.h
new file mode 100644
index 0000000000000000000000000000000000000000..8f3dd29960e8bc5c524e28e2e3fe2f15f1fc681d
--- /dev/null
+++ b/src/builtins/builtins-constructor.h
@@ -0,0 +1,22 @@
+// Copyright 2016 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.
+
+#include "src/code-stub-assembler.h"
+
+namespace v8 {
+namespace internal {
+
+typedef compiler::Node Node;
+typedef compiler::CodeAssemblerState CodeAssemblerState;
+
+class ConstructorBuiltinsAssembler : public CodeStubAssembler {
+ public:
+  explicit ConstructorBuiltinsAssembler(CodeAssemblerState* state)
+      : CodeStubAssembler(state) {}
+
+  Node* GenerateFastNewClosure(Node* shared_info, Node* context);
+};
+
+}  // namespace internal
+}  // namespace v8