Split out QuicAlarm creation from QuicConnectionHelper to new QuicAlarmFactory.

net/tools/quic/test_tools/packet_dropping_test_writer.cc

Index: net/tools/quic/test_tools/packet_dropping_test_writer.cc
diff --git a/net/tools/quic/test_tools/packet_dropping_test_writer.cc b/net/tools/quic/test_tools/packet_dropping_test_writer.cc
index 3858b7828b82504d7a38f99d2bceaa595dcad437..4d85d5a85f9d7f40f307c7ac857c90857da350e3 100644
--- a/net/tools/quic/test_tools/packet_dropping_test_writer.cc
+++ b/net/tools/quic/test_tools/packet_dropping_test_writer.cc
@@ -66,11 +66,12 @@ PacketDroppingTestWriter::PacketDroppingTestWriter()
 PacketDroppingTestWriter::~PacketDroppingTestWriter() {}
 
 void PacketDroppingTestWriter::Initialize(QuicConnectionHelperInterface* helper,
+                                          QuicAlarmFactory* alarm_factory,
                                           Delegate* on_can_write) {
   clock_ = helper->GetClock();
   write_unblocked_alarm_.reset(
-      helper->CreateAlarm(new WriteUnblockedAlarm(this)));
-  delay_alarm_.reset(helper->CreateAlarm(new DelayAlarm(this)));
+      alarm_factory->CreateAlarm(new WriteUnblockedAlarm(this)));
+  delay_alarm_.reset(alarm_factory->CreateAlarm(new DelayAlarm(this)));
   on_can_write_.reset(on_can_write);
 }