RefCounted types should not have public destructors

chrome/browser/extensions/api/identity/web_auth_flow.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_API_IDENTITY_WEB_AUTH_FLOW_H_
 #define CHROME_BROWSER_EXTENSIONS_API_IDENTITY_WEB_AUTH_FLOW_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 33 matching lines @@
    public:
     // Called when the auth flow is completed successfully.
     // |redirect_url| is the full URL the provider redirected to at the end
     // of the flow.
     virtual void OnAuthFlowSuccess(const std::string& redirect_url) = 0;
     // Called when the auth flow fails. This means that the flow did not result
     // in a successful redirect to a valid redirect URL or the user canceled
     // the flow.
     virtual void OnAuthFlowFailure() = 0;
 
-    virtual ~Delegate() { }
+   protected:
+    virtual ~Delegate() {}
   };
 
   // Interceptor interface for testing.
   class InterceptorForTests {
    public:
     virtual GURL DoIntercept(const GURL& provider_url) = 0;
     virtual ~InterceptorForTests() { }
   };
   static void SetInterceptorForTests(InterceptorForTests* interceptor);
 
@@ skipping 44 matching lines @@
 
   content::WebContents* contents_;
   WebAuthFlowWindow* window_;
 
   DISALLOW_COPY_AND_ASSIGN(WebAuthFlow);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_IDENTITY_WEB_AUTH_FLOW_H_