RefCounted types should not have public destructors, net/ edition

net/disk_cache/file.h

Index: net/disk_cache/file.h
diff --git a/net/disk_cache/file.h b/net/disk_cache/file.h
index 3617e0cbed797c7ed00c6ef47e6f1b106d46c2c5..446ccf5d5914fdded4c6cbc0d8cdda0299c8c3b8 100644
--- a/net/disk_cache/file.h
+++ b/net/disk_cache/file.h
@@ -19,11 +19,12 @@ namespace disk_cache {
 // This interface is used to support asynchronous ReadData and WriteData calls.
 class FileIOCallback {
  public:
-  virtual ~FileIOCallback() {}
-
   // Notified of the actual number of bytes read or written. This value is
   // negative if an error occurred.
   virtual void OnFileIOComplete(int bytes_copied) = 0;
+
+ protected:
+  virtual ~FileIOCallback() {}
 };
 
 // Simple wrapper around a file that allows asynchronous operations.