Support compile time constant conditional expressions

runtime/vm/ast.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_AST_H_
 #define VM_AST_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
@@ skipping 681 matching lines @@
 
   void set_true_expr(AstNode* true_expr) {
     ASSERT(true_expr != NULL);
     true_expr_ = true_expr;
   }
   void set_false_expr(AstNode* false_expr) {
     ASSERT(false_expr != NULL);
     false_expr_ = false_expr;
   }
 
+  virtual bool IsPotentiallyConst() const;
+  virtual const Instance* EvalConstExpr() const;
+
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     condition()->Visit(visitor);
     true_expr()->Visit(visitor);
     false_expr()->Visit(visitor);
   }
 
   DECLARE_COMMON_NODE_FUNCTIONS(ConditionalExprNode);
 
  private:
   AstNode* condition_;
@@ skipping 1038 matching lines @@
   const intptr_t try_index_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(InlinedFinallyNode);
 };
 
 }  // namespace dart
 
 #undef DECLARE_COMMON_NODE_FUNCTIONS
 
 #endif  // VM_AST_H_