Refactoring: Create per-connection packet writers in QuicDispatcher.

net/tools/quic/test_tools/quic_dispatcher_peer.cc

Index: net/tools/quic/test_tools/quic_dispatcher_peer.cc
diff --git a/net/tools/quic/test_tools/quic_dispatcher_peer.cc b/net/tools/quic/test_tools/quic_dispatcher_peer.cc
index 26ff490a0b440bf3f25d58bdcaf791e26b473165..190042031fd8881bba26854b48934c03e550404e 100644
--- a/net/tools/quic/test_tools/quic_dispatcher_peer.cc
+++ b/net/tools/quic/test_tools/quic_dispatcher_peer.cc
@@ -31,6 +31,13 @@ QuicPacketWriter* QuicDispatcherPeer::GetWriter(QuicDispatcher* dispatcher) {
 }
 
 // static
+void QuicDispatcherPeer::SetPacketWriterFactory(
+    QuicDispatcher* dispatcher,
+    QuicDispatcher::PacketWriterFactory* packet_writer_factory) {
+  dispatcher->packet_writer_factory_.reset(packet_writer_factory);
+}
+
+// static
 QuicEpollConnectionHelper* QuicDispatcherPeer::GetHelper(
     QuicDispatcher* dispatcher) {
   return dispatcher->helper_.get();