Reland r113263 rebased after revert of r113249.

net/disk_cache/in_flight_backend_io.cc

Index: net/disk_cache/in_flight_backend_io.cc
diff --git a/net/disk_cache/in_flight_backend_io.cc b/net/disk_cache/in_flight_backend_io.cc
index eb42b2a645a19a945e8d3115dc5cf56a216d06af..868ceed6fbd3b54ad354a9563fd57db7932f52e1 100644
--- a/net/disk_cache/in_flight_backend_io.cc
+++ b/net/disk_cache/in_flight_backend_io.cc
@@ -384,6 +384,13 @@ void InFlightBackendIO::OpenNextEntry(void** iter, Entry** next_entry,
   PostOperation(operation);
 }
 
+void InFlightBackendIO::OpenNextEntry(void** iter, Entry** next_entry,
+                                      const net::CompletionCallback& callback) {
+  scoped_refptr<BackendIO> operation(new BackendIO(this, backend_, callback));
+  operation->OpenNextEntry(iter, next_entry);
+  PostOperation(operation);
+}
+
 void InFlightBackendIO::OpenPrevEntry(void** iter, Entry** prev_entry,
                                       OldCompletionCallback* callback) {
   scoped_refptr<BackendIO> operation(new BackendIO(this, backend_, callback));