Introduce builtin for Array.unshift function.

src/builtins.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 31 matching lines @@
 #define BUILTIN_LIST_C(V)                                           \
   V(Illegal, NO_EXTRA_ARGUMENTS)                                    \
                                                                     \
   V(EmptyFunction, NO_EXTRA_ARGUMENTS)                              \
                                                                     \
   V(ArrayCodeGeneric, NO_EXTRA_ARGUMENTS)                           \
                                                                     \
   V(ArrayPush, NO_EXTRA_ARGUMENTS)                                  \
   V(ArrayPop, NO_EXTRA_ARGUMENTS)                                   \
   V(ArrayShift, NO_EXTRA_ARGUMENTS)                                 \
+  V(ArrayUnshift, NO_EXTRA_ARGUMENTS)                               \
                                                                     \
   V(HandleApiCall, NEEDS_CALLED_FUNCTION)                           \
   V(FastHandleApiCall, NO_EXTRA_ARGUMENTS)                          \
   V(HandleApiCallConstruct, NEEDS_CALLED_FUNCTION)                  \
   V(HandleApiCallAsFunction, NO_EXTRA_ARGUMENTS)                    \
   V(HandleApiCallAsConstructor, NO_EXTRA_ARGUMENTS)
 
 
 // Define list of builtins implemented in assembly.
 #define BUILTIN_LIST_A(V)                                                 \
@@ skipping 184 matching lines @@
   static void Generate_FunctionCall(MacroAssembler* masm);
   static void Generate_FunctionApply(MacroAssembler* masm);
 
   static void Generate_ArrayCode(MacroAssembler* masm);
   static void Generate_ArrayConstructCode(MacroAssembler* masm);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_BUILTINS_H_