Refactoring: Create per-connection packet writers in QuicDispatcher.

net/tools/quic/quic_server_test.cc

Index: net/tools/quic/quic_server_test.cc
diff --git a/net/tools/quic/quic_server_test.cc b/net/tools/quic/quic_server_test.cc
index e2d7c4f3288f363689eb9a47a72b32ec3cd38b5f..1107dedb1c84bf0ee6a1fc8bbef77b1bae979f05 100644
--- a/net/tools/quic/quic_server_test.cc
+++ b/net/tools/quic/quic_server_test.cc
@@ -21,7 +21,10 @@ class QuicServerDispatchPacketTest : public ::testing::Test {
  public:
   QuicServerDispatchPacketTest()
       : crypto_config_("blah", QuicRandom::GetInstance()),
-        dispatcher_(config_, crypto_config_, &eps_) {
+        dispatcher_(config_,
+                    crypto_config_,
+                    new QuicDispatcher::DefaultPacketWriterFactory(),
+                    &eps_) {
     dispatcher_.Initialize(1234);
   }