RefCounted types should not have public destructors, delegate cleanup

content/browser/download/download_item_impl.h

Index: content/browser/download/download_item_impl.h
diff --git a/content/browser/download/download_item_impl.h b/content/browser/download/download_item_impl.h
index 1bcdcd43490117b36c119b764de75d0601d34743..31b4a4c708f83702f893a4c4368dead37a3f2009 100644
--- a/content/browser/download/download_item_impl.h
+++ b/content/browser/download/download_item_impl.h
@@ -37,7 +37,6 @@ class CONTENT_EXPORT DownloadItemImpl : public content::DownloadItem {
   class CONTENT_EXPORT Delegate {
    public:
     Delegate();
-    virtual ~Delegate();
 
     // Used for catching use-after-free errors.
     void Attach();
@@ -73,6 +72,9 @@ class CONTENT_EXPORT DownloadItemImpl : public content::DownloadItem {
     // 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_;