Enable stepping into callback passed to builtins (e.g. Array.forEach).

src/runtime.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 79 matching lines @@
   F(DeoptimizeFunction, 1, 1) \
   F(RunningInSimulator, 0, 1) \
   F(OptimizeFunctionOnNextCall, -1, 1) \
   F(GetOptimizationStatus, 1, 1) \
   F(GetOptimizationCount, 1, 1) \
   F(CompileForOnStackReplacement, 1, 1) \
   F(SetNewFunctionAttributes, 1, 1) \
   F(AllocateInNewSpace, 1, 1) \
   F(SetNativeFlag, 1, 1) \
   F(StoreArrayLiteralElement, 5, 1) \
+  F(DebugStepIntoBuiltinCallback, 1, 1) \
+  F(PrepareBreakSlotsForCallback, 1, 1) \
   \
   /* Array join support */ \
   F(PushIfAbsent, 2, 1) \
   F(ArrayConcat, 1, 1) \
   \
   /* Conversions */ \
   F(ToBool, 1, 1) \
   F(Typeof, 1, 1) \
   \
   F(StringToNumber, 1, 1) \
@@ skipping 588 matching lines @@
 //---------------------------------------------------------------------------
 // Constants used by interface to runtime functions.
 
 class DeclareGlobalsEvalFlag:     public BitField<bool,         0, 1> {};
 class DeclareGlobalsNativeFlag:   public BitField<bool,         1, 1> {};
 class DeclareGlobalsLanguageMode: public BitField<LanguageMode, 2, 2> {};
 
 } }  // namespace v8::internal
 
 #endif  // V8_RUNTIME_H_