[es6] Implement Date.prototype[@@toPrimitive] as C++ builtin.

src/builtins.h

 // Copyright 2011 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_BUILTINS_H_
 #define V8_BUILTINS_H_
 
 #include "src/handles.h"
 
 namespace v8 {
@@ skipping 39 matching lines @@
   V(EmptyFunction, NO_EXTRA_ARGUMENTS)                       \
                                                              \
   V(ArrayPush, NO_EXTRA_ARGUMENTS)                           \
   V(ArrayPop, NO_EXTRA_ARGUMENTS)                            \
   V(ArrayShift, NO_EXTRA_ARGUMENTS)                          \
   V(ArrayUnshift, NO_EXTRA_ARGUMENTS)                        \
   V(ArraySlice, NO_EXTRA_ARGUMENTS)                          \
   V(ArraySplice, NO_EXTRA_ARGUMENTS)                         \
   V(ArrayConcat, NO_EXTRA_ARGUMENTS)                         \
                                                              \
+  V(DateToPrimitive, NO_EXTRA_ARGUMENTS)                     \
+                                                             \
   V(HandleApiCall, NEEDS_CALLED_FUNCTION)                    \
   V(HandleApiCallConstruct, NEEDS_CALLED_FUNCTION)           \
   V(HandleApiCallAsFunction, NO_EXTRA_ARGUMENTS)             \
   V(HandleApiCallAsConstructor, NO_EXTRA_ARGUMENTS)          \
                                                              \
   V(RestrictedFunctionPropertiesThrower, NO_EXTRA_ARGUMENTS) \
   V(RestrictedStrictArgumentsPropertiesThrower, NO_EXTRA_ARGUMENTS)
 
 // Define list of builtins implemented in assembly.
 #define BUILTIN_LIST_A(V)                                                    \
@@ skipping 221 matching lines @@
 
   friend class BuiltinFunctionTable;
   friend class Isolate;
 
   DISALLOW_COPY_AND_ASSIGN(Builtins);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_BUILTINS_H_