Adds dynamic FEC on/off switch in packet creator. Tightens use of

net/quic/test_tools/quic_packet_creator_peer.cc

Index: net/quic/test_tools/quic_packet_creator_peer.cc
diff --git a/net/quic/test_tools/quic_packet_creator_peer.cc b/net/quic/test_tools/quic_packet_creator_peer.cc
index 1acdf244f2ff9a63d0db4990aba1d1f7bb811c48..07658e59c22af3bdba740ab65f3246a8303f81c6 100644
--- a/net/quic/test_tools/quic_packet_creator_peer.cc
+++ b/net/quic/test_tools/quic_packet_creator_peer.cc
@@ -39,5 +39,13 @@ void QuicPacketCreatorPeer::SetIsServer(QuicPacketCreator* creator,
   creator->is_server_ = is_server;
 }
 
+// static
+bool QuicPacketCreatorPeer::SwitchFecProtectionOn(
+    QuicPacketCreator* creator, size_t max_packets_per_fec_group) {
+  creator->set_max_packets_per_fec_group(max_packets_per_fec_group);
+  creator->StartFecProtectingPackets();
+  return creator->IsFecProtected();
+}
+
 }  // namespace test
 }  // namespace net