RefCounted types should not have public destructors, delegate cleanup

chrome/browser/extensions/bundle_installer.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 CHROME_BROWSER_EXTENSIONS_BUNDLE_INSTALLER_H_
 #define CHROME_BROWSER_EXTENSIONS_BUNDLE_INSTALLER_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 33 matching lines @@
                         public base::RefCountedThreadSafe<BundleInstaller> {
  public:
   // Auto approve or cancel the permission prompt.
   static void SetAutoApproveForTesting(bool approve);
 
   class Delegate {
    public:
     virtual void OnBundleInstallApproved() {}
     virtual void OnBundleInstallCanceled(bool user_initiated) {}
     virtual void OnBundleInstallCompleted() {}
+
+   protected:
+    virtual ~Delegate() {}
   };
 
   // Represents an individual member of the bundle.
   struct Item {
     // Items are in the PENDING state until they've been installed, or the
     // install has failed or been canceled.
     enum State {
       STATE_PENDING,
       STATE_INSTALLED,
       STATE_FAILED
@@ skipping 126 matching lines @@
   scoped_ptr<ExtensionInstallUI> install_ui_;
 
   Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(BundleInstaller);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_BUNDLE_INSTALLER_H_