Move the per-ast-node statement position to only statement node types....

src/ast.h

Index: src/ast.h
===================================================================
--- src/ast.h	(revision 2975)
+++ src/ast.h	(working copy)
@@ -116,7 +116,6 @@
 
 class AstNode: public ZoneObject {
  public:
-  AstNode(): statement_pos_(RelocInfo::kNoPosition) { }
   virtual ~AstNode() { }
   virtual void Accept(AstVisitor* v) = 0;
 
@@ -140,21 +139,23 @@
   virtual MaterializedLiteral* AsMaterializedLiteral() { return NULL; }
   virtual ObjectLiteral* AsObjectLiteral() { return NULL; }
   virtual ArrayLiteral* AsArrayLiteral() { return NULL; }
-
-  void set_statement_pos(int statement_pos) { statement_pos_ = statement_pos; }
-  int statement_pos() const { return statement_pos_; }
-
- private:
-  int statement_pos_;
 };
 
 
 class Statement: public AstNode {
  public:
+  Statement() : statement_pos_(RelocInfo::kNoPosition) {}
+
   virtual Statement* AsStatement()  { return this; }
   virtual ReturnStatement* AsReturnStatement() { return NULL; }
 
   bool IsEmpty() { return AsEmptyStatement() != NULL; }
+
+  void set_statement_pos(int statement_pos) { statement_pos_ = statement_pos; }
+  int statement_pos() const { return statement_pos_; }
+
+ private:
+  int statement_pos_;
 };