Don't copy the QuicAckFrame into the QuicPacketGenerator. Protected by quic_dont_copy_acks.

net/quic/quic_multipath_received_packet_manager_test.cc

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_multipath_received_packet_manager.h"
 
 #include "net/quic/quic_connection_stats.h"
+#include "net/quic/quic_flags.h"
 #include "net/quic/test_tools/quic_test_utils.h"
 #include "net/test/gtest_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using testing::Return;
 using testing::_;
 
 namespace net {
 namespace test {
@@ skipping 102 matching lines @@
   EXPECT_TRUE(multipath_manager_.IsAwaitingPacket(kDefaultPathId,
                                                   header_.packet_number));
   EXPECT_FALSE(
       multipath_manager_.IsAwaitingPacket(kPathId1, header_.packet_number));
   EXPECT_DFATAL(
       multipath_manager_.IsAwaitingPacket(kPathId2, header_.packet_number),
       "Check whether a packet is awaited on a non-existent path");
 }
 
 TEST_F(QuicMultipathReceivedPacketManagerTest, UpdateReceivedPacketInfo) {
+  FLAGS_quic_dont_copy_acks = false;
   std::vector<QuicAckFrame> ack_frames;
   EXPECT_EQ(static_cast<size_t>(0), ack_frames.size());
   EXPECT_CALL(*manager_0_, ack_frame_updated()).WillOnce(Return(false));
   EXPECT_CALL(*manager_1_, ack_frame_updated()).WillRepeatedly(Return(false));
   multipath_manager_.UpdateReceivedPacketInfo(&ack_frames, QuicTime::Zero(),
                                               /*force_all_paths=*/false);
   EXPECT_EQ(static_cast<size_t>(0), ack_frames.size());
   EXPECT_CALL(*manager_0_, ack_frame_updated()).WillOnce(Return(true));
   multipath_manager_.UpdateReceivedPacketInfo(&ack_frames, QuicTime::Zero(),
                                               /*force_all_paths=*/false);
@@ skipping 27 matching lines @@
   EXPECT_CALL(*manager_1_, HasNewMissingPackets()).WillOnce(Return(false));
   EXPECT_TRUE(multipath_manager_.HasNewMissingPackets(kDefaultPathId));
   EXPECT_FALSE(multipath_manager_.HasNewMissingPackets(kPathId1));
   EXPECT_DFATAL(multipath_manager_.HasNewMissingPackets(kPathId2),
                 "Check whether has new missing packets on a non-existent path");
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net