Update from https://crrev.com/309415

net/quic/quic_packet_generator_test.cc

Index: net/quic/quic_packet_generator_test.cc
diff --git a/net/quic/quic_packet_generator_test.cc b/net/quic/quic_packet_generator_test.cc
index ac99144fc2af5157929a4254d604a2397db7d073..7eea015f022342ed4ff2050a82247b695bde0c69 100644
--- a/net/quic/quic_packet_generator_test.cc
+++ b/net/quic/quic_packet_generator_test.cc
@@ -10,6 +10,7 @@
 #include "net/quic/crypto/null_encrypter.h"
 #include "net/quic/crypto/quic_decrypter.h"
 #include "net/quic/crypto/quic_encrypter.h"
+#include "net/quic/quic_flags.h"
 #include "net/quic/quic_utils.h"
 #include "net/quic/test_tools/quic_packet_creator_peer.h"
 #include "net/quic/test_tools/quic_packet_generator_peer.h"
@@ -315,6 +316,30 @@ TEST_F(QuicPacketGeneratorTest,
   CheckPacketContains(contents, packet_);
 }
 
+TEST_F(QuicPacketGeneratorTest, ShouldSendAck_MultipleCalls) {
+  ValueRestore<bool> old_flag(&FLAGS_quic_disallow_multiple_pending_ack_frames,
+                              true);
+
+  // Make sure that calling SetShouldSendAck multiple times does not result in a
+  // crash. Previously this would result in multiple QuicFrames queued in the
+  // packet generator, with all but the last with internal pointers to freed
+  // memory.
+  delegate_.SetCanWriteAnything();
+
+  // Only one AckFrame should be created.
+  EXPECT_CALL(delegate_, CreateAckFrame())
+      .Times(1)
+      .WillOnce(Return(CreateAckFrame()));
+  EXPECT_CALL(delegate_, OnSerializedPacket(_))
+      .Times(1)
+      .WillOnce(SaveArg<0>(&packet_));
+
+  generator_.StartBatchOperations();
+  generator_.SetShouldSendAck(false, false);
+  generator_.SetShouldSendAck(false, false);
+  generator_.FinishBatchOperations();
+}
+
 TEST_F(QuicPacketGeneratorTest, AddControlFrame_NotWritable) {
   delegate_.SetCanNotWrite();