Added mutation of locals to debugger

src/frames.h

Index: src/frames.h
===================================================================
--- src/frames.h	(revision 2164)
+++ src/frames.h	(working copy)
@@ -376,6 +376,7 @@
 
   // Access the parameters.
   Object* GetParameter(int index) const;
+  void SetParameter(int index, Object* value);
   int ComputeParametersCount() const;
 
   // Temporary way of getting access to the number of parameters
@@ -414,6 +415,9 @@
 
   virtual Address GetCallerStackPointer() const;
 
+  // Returns the address of the n'th parameter stack element.
+  inline Address GetParameterAddress(int n) const;
+
   // When this mode is enabled it is not allowed to access heap objects.
   // This is a special mode used when gathering stack samples in profiler.
   // A shortcoming is that caller's SP value will be calculated incorrectly