Minor refactoring in QuicDispatcher. No functional change, not flag-protected.

net/quic/core/quic_sent_packet_manager_test.cc

Index: net/quic/core/quic_sent_packet_manager_test.cc
diff --git a/net/quic/core/quic_sent_packet_manager_test.cc b/net/quic/core/quic_sent_packet_manager_test.cc
index 058009375c3f9792d12bbb528b4dada2d18c41fb..8f3a4f6f0df67785b533abb1f7425de295a8c272 100644
--- a/net/quic/core/quic_sent_packet_manager_test.cc
+++ b/net/quic/core/quic_sent_packet_manager_test.cc
@@ -564,9 +564,6 @@ TEST_P(QuicSentPacketManagerTest, AckOriginalTransmission) {
   {
     QuicAckFrame ack_frame = InitAckFrame(4);
     NackPackets(2, 3, &ack_frame);
-    EXPECT_CALL(*loss_algorithm, DetectLosses(_, _, _, _, _));
-    EXPECT_CALL(*loss_algorithm, SpuriousRetransmitDetected(_, _, _, 5));
-    manager_.OnIncomingAck(ack_frame, clock_.Now());
   }
 }