reland 16744: add context save for GenerateFastApiCall

include/v8.h

 // Copyright 2012 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 2346 matching lines @@
   V8_INLINE int Length() const;
   V8_INLINE Local<Value> operator[](int i) const;
   V8_INLINE Local<Function> Callee() const;
   V8_INLINE Local<Object> This() const;
   V8_INLINE Local<Object> Holder() const;
   V8_INLINE bool IsConstructCall() const;
   V8_INLINE Local<Value> Data() const;
   V8_INLINE Isolate* GetIsolate() const;
   V8_INLINE ReturnValue<T> GetReturnValue() const;
   // This shouldn't be public, but the arm compiler needs it.
-  static const int kArgsLength = 6;
+  static const int kArgsLength = 7;
 
  protected:
   friend class internal::FunctionCallbackArguments;
   friend class internal::CustomArguments<FunctionCallbackInfo>;
   static const int kReturnValueIndex = 0;
   static const int kReturnValueDefaultValueIndex = -1;
   static const int kIsolateIndex = -2;
   static const int kDataIndex = -3;
   static const int kCalleeIndex = -4;
   static const int kHolderIndex = -5;
+  static const int kContextSaveIndex = -6;
 
   V8_INLINE FunctionCallbackInfo(internal::Object** implicit_args,
                    internal::Object** values,
                    int length,
                    bool is_construct_call);
   internal::Object** implicit_args_;
   internal::Object** values_;
   int length_;
   bool is_construct_call_;
 };
@@ skipping 4043 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_