Clean up some messiness in Scopes.

src/variables.cc

Index: src/variables.cc
diff --git a/src/variables.cc b/src/variables.cc
index f46a54d6ef5daa1e0cd5b65301eb58f817bbb608..504e2244234d5e4746a4147223541aa9acace82c 100644
--- a/src/variables.cc
+++ b/src/variables.cc
@@ -70,24 +70,19 @@ const char* Variable::Mode2String(Mode mode) {
 }
 
 
-Property* Variable::AsProperty() {
+Property* Variable::AsProperty() const {
   return rewrite_ == NULL ? NULL : rewrite_->AsProperty();
 }
 
 
-Variable* Variable::AsVariable()  {
-  return rewrite_ == NULL || rewrite_->AsSlot() != NULL ? this : NULL;
-}
-
-
-Slot* Variable::slot() const {
-  return rewrite_ != NULL ? rewrite_->AsSlot() : NULL;
+Slot* Variable::AsSlot() const {
+  return rewrite_ == NULL ? NULL : rewrite_->AsSlot();
 }
 
 
 bool Variable::IsStackAllocated() const {
-  Slot* s = slot();
-  return s != NULL && s->IsStackAllocated();
+  Slot* slot = AsSlot();
+  return slot != NULL && slot->IsStackAllocated();
 }