Issue 2399 part 1: In debugger allow modifying local variable values

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 412 matching lines @@
   F(DebugPropertyIndexFromDetails, 1, 1) \
   F(DebugNamedInterceptorPropertyValue, 2, 1) \
   F(DebugIndexedInterceptorElementValue, 2, 1) \
   F(CheckExecutionState, 1, 1) \
   F(GetFrameCount, 1, 1) \
   F(GetFrameDetails, 2, 1) \
   F(GetScopeCount, 2, 1) \
   F(GetScopeDetails, 4, 1) \
   F(GetFunctionScopeCount, 1, 1) \
   F(GetFunctionScopeDetails, 2, 1) \
+  F(SetScopeVariableValue, 6, 1) \
   F(DebugPrintScopes, 0, 1) \
   F(GetThreadCount, 1, 1) \
   F(GetThreadDetails, 2, 1) \
   F(SetDisableBreak, 1, 1) \
   F(GetBreakLocations, 1, 1) \
   F(SetFunctionBreakPoint, 3, 1) \
   F(SetScriptBreakPoint, 3, 1) \
   F(ClearBreakPoint, 1, 1) \
   F(ChangeBreakOnException, 2, 1) \
   F(IsBreakOnException, 1, 1) \
@@ skipping 272 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_