Pass value and use std::move instead of const reference for ack listeners.

net/quic/core/quic_spdy_session.cc

Index: net/quic/core/quic_spdy_session.cc
diff --git a/net/quic/core/quic_spdy_session.cc b/net/quic/core/quic_spdy_session.cc
index 0fe39fa590e5e1a3e83ceaef5f178a04d5b08d30..ba6a4192dedaf74f9bd83f31c0bb823c86e9eb4a 100644
--- a/net/quic/core/quic_spdy_session.cc
+++ b/net/quic/core/quic_spdy_session.cc
@@ -74,9 +74,9 @@ size_t QuicSpdySession::WriteHeaders(
     SpdyHeaderBlock headers,
     bool fin,
     SpdyPriority priority,
-    const scoped_refptr<QuicAckListenerInterface>& ack_notifier_delegate) {
+    scoped_refptr<QuicAckListenerInterface> ack_notifier_delegate) {
   return headers_stream_->WriteHeaders(id, std::move(headers), fin, priority,
-                                       ack_notifier_delegate);
+                                       std::move(ack_notifier_delegate));
 }
 
 void QuicSpdySession::OnHeadersHeadOfLineBlocking(QuicTime::Delta delta) {