RefCounted types should not have public destructors, delegate cleanup

content/browser/download/download_item_impl.h

 // Copyright (c) 2012 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_DOWNLOAD_DOWNLOAD_ITEM_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_H_
 #pragma once
 
 #include <string>
 
@@ skipping 19 matching lines @@
   // Delegate is defined in DownloadItemImpl (rather than DownloadItem)
   // as it's relevant to the class implementation (class methods need to
   // call into it) and doesn't have anything to do with its interface.
   // Despite this, the delegate methods take DownloadItems as arguments
   // (rather than DownloadItemImpls) so that classes that inherit from it
   // can be used with DownloadItem mocks rather than being tied to
   // DownloadItemImpls.
   class CONTENT_EXPORT Delegate {
    public:
     Delegate();
-    virtual ~Delegate();
 
     // Used for catching use-after-free errors.
     void Attach();
     void Detach();
 
     // Tests if a file type should be opened automatically.
     virtual bool ShouldOpenFileBasedOnExtension(const FilePath& path) = 0;
 
     // Allows the delegate to override the opening of a download. If it returns
     // true then it's reponsible for opening the item.
@@ skipping 15 matching lines @@
     // Handle any delegate portions of a state change operation on the
     // DownloadItem.
     virtual void DownloadCancelled(DownloadItem* download) = 0;
     virtual void DownloadCompleted(DownloadItem* download) = 0;
     virtual void DownloadOpened(DownloadItem* download) = 0;
     virtual void DownloadRemoved(DownloadItem* download) = 0;
 
     // Assert consistent state for delgate object at various transitions.
     virtual void AssertStateConsistent(DownloadItem* download) const = 0;
 
+   protected:
+    virtual ~Delegate();
+
    private:
     // For "Outlives attached DownloadItemImpl" invariant assertion.
     int count_;
   };
 
   // Note that it is the responsibility of the caller to ensure that a
   // DownloadItemImpl::Delegate passed to a DownloadItemImpl constructor
   // outlives the DownloadItemImpl.
 
   // Constructing from persistent store:
@@ skipping 305 matching lines @@
   // are owned by the DownloadItemImpl.
   std::map<const void*, ExternalData*> external_data_map_;
 
   // Net log to use for this download.
   const net::BoundNetLog bound_net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemImpl);
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_H_