Preparatory refactoring-only steps for inlining accessors.

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 8c9606a2db92da928fcab1f1aa131adea5423e78..0a7eb0008cb3d17f2f4d0637c5ade7550b10fc0f 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -1512,6 +1512,7 @@ class Property: public Expression {
   Expression* obj() const { return obj_; }
   Expression* key() const { return key_; }
   virtual int position() const { return pos_; }
+  int ReturnId() const { return return_id_; }
 
   bool IsStringLength() const { return is_string_length_; }
   bool IsStringAccess() const { return is_string_access_; }
@@ -1535,6 +1536,7 @@ class Property: public Expression {
         obj_(obj),
         key_(key),
         pos_(pos),
+        return_id_(GetNextId(isolate)),
         is_monomorphic_(false),
         is_uninitialized_(false),
         is_array_length_(false),
@@ -1546,6 +1548,7 @@ class Property: public Expression {
   Expression* obj_;
   Expression* key_;
   int pos_;
+  const int return_id_;
 
   SmallMapList receiver_types_;
   bool is_monomorphic_ : 1;