Move Object.assign implementation to C++

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/base/flags.h"
 #include "src/handles.h"
 
@@ skipping 49 matching lines @@
   V(ArrayIsArray, kNone)                        \
   V(ArrayPop, kNone)                            \
   V(ArrayPush, kNone)                           \
   V(ArrayShift, kNone)                          \
   V(ArraySlice, kNone)                          \
   V(ArraySplice, kNone)                         \
   V(ArrayUnshift, kNone)                        \
                                                 \
   V(DateToPrimitive, kNone)                     \
                                                 \
+  V(ObjectAssign, kNone)                        \
   V(ObjectProtoToString, kNone)                 \
                                                 \
   V(ProxyConstructor, kNone)                    \
   V(ProxyConstructor_ConstructStub, kTarget)    \
                                                 \
   V(ReflectDefineProperty, kNone)               \
   V(ReflectDeleteProperty, kNone)               \
   V(ReflectGet, kNone)                          \
   V(ReflectGetOwnPropertyDescriptor, kNone)     \
   V(ReflectGetPrototypeOf, kNone)               \
@@ skipping 308 matching lines @@
   friend class BuiltinFunctionTable;
   friend class Isolate;
 
   DISALLOW_COPY_AND_ASSIGN(Builtins);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_BUILTINS_H_