Revert "Save and restore feedback from JIT."

runtime/vm/program_visitor.h

-// Copyright (c) 2015, 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 RUNTIME_VM_PROGRAM_VISITOR_H_
-#define RUNTIME_VM_PROGRAM_VISITOR_H_
-
-#include "vm/allocation.h"
-
-namespace dart {
-
-class Function;
-class Class;
-
-template <typename T>
-class Visitor : public ValueObject {
- public:
-  virtual ~Visitor() {}
-  virtual void Visit(const T& obj) = 0;
-};
-
-typedef Visitor<Function> FunctionVisitor;
-typedef Visitor<Class> ClassVisitor;
-
-class ProgramVisitor : public AllStatic {
- public:
-  static void VisitFunctions(FunctionVisitor* visitor);
-  static void VisitClasses(ClassVisitor* visitor);
-};
-
-}  // namespace dart
-
-#endif  // RUNTIME_VM_PROGRAM_VISITOR_H_