Always iterate outgoing arguments as a part of caller frame.

src/frames-inl.h

Index: src/frames-inl.h
diff --git a/src/frames-inl.h b/src/frames-inl.h
index 236db05a7060f17251f8a411e3c6fcdaefe749e6..5951806245bca49305c56f5049a6fc19d11e9a37 100644
--- a/src/frames-inl.h
+++ b/src/frames-inl.h
@@ -148,15 +148,26 @@ inline bool StandardFrame::IsConstructFrame(Address fp) {
 }
 
 
+Address JavaScriptFrame::GetParameterSlot(int index) const {
+  int param_count = ComputeParametersCount();
+  ASSERT(-1 <= index && index < param_count);
+  int parameter_offset = (param_count - index - 1) * kPointerSize;
+  return caller_sp() + parameter_offset;
+}
+
+
+Object* JavaScriptFrame::GetParameter(int index) const {
+  return Memory::Object_at(GetParameterSlot(index));
+}
+
+
 inline Object* JavaScriptFrame::receiver() const {
-  const int offset = JavaScriptFrameConstants::kReceiverOffset;
-  return Memory::Object_at(caller_sp() + offset);
+  return GetParameter(-1);
 }
 
 
 inline void JavaScriptFrame::set_receiver(Object* value) {
-  const int offset = JavaScriptFrameConstants::kReceiverOffset;
-  Memory::Object_at(caller_sp() + offset) = value;
+  Memory::Object_at(GetParameterSlot(-1)) = value;
 }