Virtual destructors should have virtual keyword.

content/browser/mock_resource_context.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MOCK_RESOURCE_CONTEXT_H_
 #define CONTENT_BROWSER_MOCK_RESOURCE_CONTEXT_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "content/browser/resource_context.h"
 
 namespace base {
 template <typename T>
 struct DefaultLazyInstanceTraits;
 }  // namespace base
 
 namespace content {
 
 class MockResourceContext : public ResourceContext {
  public:
   static const ResourceContext& GetInstance();
 
  private:
   friend struct base::DefaultLazyInstanceTraits<MockResourceContext>;
 
   MockResourceContext();
-  ~MockResourceContext();
+  virtual ~MockResourceContext();
   virtual void EnsureInitialized() const OVERRIDE;
 
   const scoped_refptr<net::URLRequestContext> test_request_context_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MOCK_RESOURCE_CONTEXT_H_