Change the API of disk_cache::CreateCacheBackend to use scoped_ptr

net/http/http_cache.h

Index: net/http/http_cache.h
diff --git a/net/http/http_cache.h b/net/http/http_cache.h
index c4012654eaa966425a9cc93c2e51b669ed4ebcb9..db2db6906d5ad5a0125f70496f0109b3ae44564a 100644
--- a/net/http/http_cache.h
+++ b/net/http/http_cache.h
@@ -89,7 +89,7 @@ class NET_EXPORT HttpCache : public HttpTransactionFactory,
     // The implementation must not access the factory object after invoking the
     // |callback| because the object can be deleted from within the callback.
     virtual int CreateBackend(NetLog* net_log,
-                              disk_cache::Backend** backend,
+                              scoped_ptr<disk_cache::Backend>* backend,
                               const CompletionCallback& callback) = 0;
   };
 
@@ -109,7 +109,7 @@ class NET_EXPORT HttpCache : public HttpTransactionFactory,
 
     // BackendFactory implementation.
     virtual int CreateBackend(NetLog* net_log,
-                              disk_cache::Backend** backend,
+                              scoped_ptr<disk_cache::Backend>* backend,
                               const CompletionCallback& callback) OVERRIDE;
 
    private: