Always iterate outgoing arguments as a part of caller frame.

src/frames.h

Index: src/frames.h
diff --git a/src/frames.h b/src/frames.h
index d6307f09975db7e0ddc973173e98dbc8a74702ec..2e43385aff997fa852b1f5ed88163c047a9feb97 100644
--- a/src/frames.h
+++ b/src/frames.h
@@ -463,8 +463,11 @@ class JavaScriptFrame: public StandardFrame {
   inline void set_receiver(Object* value);
 
   // Access the parameters.
-  Object* GetParameter(int index) const;
-  int ComputeParametersCount() const;
+  inline Address GetParameterSlot(int index) const;
+  inline Object* GetParameter(int index) const;
+  inline int ComputeParametersCount() const {
+    return GetNumberOfIncomingArguments();
+  }
 
   // Check if this frame is a constructor frame invoked through 'new'.
   bool IsConstructor() const;
@@ -502,6 +505,8 @@ class JavaScriptFrame: public StandardFrame {
 
   virtual Address GetCallerStackPointer() const;
 
+  virtual int GetNumberOfIncomingArguments() const;
+
   // Garbage collection support. Iterates over incoming arguments,
   // receiver, and any callee-saved registers.
   void IterateArguments(ObjectVisitor* v) const;
@@ -562,6 +567,10 @@ class ArgumentsAdaptorFrame: public JavaScriptFrame {
   explicit ArgumentsAdaptorFrame(StackFrameIterator* iterator)
       : JavaScriptFrame(iterator) { }
 
+  virtual int GetNumberOfIncomingArguments() const {
+     return Smi::cast(GetExpression(0))->value();
+  }
+
   virtual Address GetCallerStackPointer() const;
 
  private: