Replace QuicAckListenerInterface* with scoped_refptr<QuicAckListenerInterface>.

net/quic/chromium/quic_chromium_client_stream.h

Index: net/quic/chromium/quic_chromium_client_stream.h
diff --git a/net/quic/chromium/quic_chromium_client_stream.h b/net/quic/chromium/quic_chromium_client_stream.h
index f34be2251ee4516b6c95b05ddd3d68cf468c23c5..2c9440a2d62071f0e94a122abc1dc0a6bbbf6288 100644
--- a/net/quic/chromium/quic_chromium_client_stream.h
+++ b/net/quic/chromium/quic_chromium_client_stream.h
@@ -80,7 +80,8 @@ class NET_EXPORT_PRIVATE QuicChromiumClientStream : public QuicSpdyStream {
   void OnCanWrite() override;
   size_t WriteHeaders(SpdyHeaderBlock header_block,
                       bool fin,
-                      QuicAckListenerInterface* ack_notifier_delegate) override;
+                      const scoped_refptr<QuicAckListenerInterface>&
+                          ack_notifier_delegate) override;
   SpdyPriority priority() const override;
 
   // While the server's set_priority shouldn't be called externally, the creator