pure_virtual_trace.h revision a1401311d1ab56c4ed0a474bd38c108f75cb0cd9 
1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef PURE_VIRTUAL_BASE_H_
6#define PURE_VIRTUAL_BASE_H_
7
8#include "heap/stubs.h"
9
10namespace WebCore {
11
12class A : public GarbageCollected<A> {
13public:
14    virtual void trace(Visitor*) = 0;
15};
16
17class B : public A {
18public:
19    // Does not need a trace method.
20};
21
22class C : public B {
23public:
24    void trace(Visitor*);
25private:
26    Member<A> m_a;
27};
28
29}
30
31#endif
32