[Code Stubs] Convert FastNewClosureStub to a TurboFanCodeStub.

src/contexts.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.
 
 #ifndef V8_CONTEXTS_H_
 #define V8_CONTEXTS_H_
 
 #include "src/heap/heap.h"
 #include "src/objects.h"
 
@@ skipping 508 matching lines @@
                         int* index,
                         PropertyAttributes* attributes,
                         BindingFlags* binding_flags);
 
   // Code generation support.
   static int SlotOffset(int index) {
     return kHeaderSize + index * kPointerSize - kHeapObjectTag;
   }
 
   static int FunctionMapIndex(LanguageMode language_mode, FunctionKind kind) {
+    // Note: Must be kept in sync with FastNewClosureStub::Generate.
     if (IsGeneratorFunction(kind)) {
       return is_strict(language_mode) ? STRICT_GENERATOR_FUNCTION_MAP_INDEX
                                       : SLOPPY_GENERATOR_FUNCTION_MAP_INDEX;
     }
 
     if (IsAsyncFunction(kind)) {
       return is_strict(language_mode) ? STRICT_ASYNC_FUNCTION_MAP_INDEX
                                       : SLOPPY_ASYNC_FUNCTION_MAP_INDEX;
     }
 
@@ skipping 36 matching lines @@
 #endif
 
   STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
   STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CONTEXTS_H_