Fix to make sure QuicStreamSequencerBuffer release memory in time.

net/quic/core/quic_stream_sequencer_buffer_test.cc

Index: net/quic/core/quic_stream_sequencer_buffer_test.cc
diff --git a/net/quic/core/quic_stream_sequencer_buffer_test.cc b/net/quic/core/quic_stream_sequencer_buffer_test.cc
index b020e6992700ad85431c4b5297e71c930121e4c2..655b13a62b78bddf6f440f8c6775e8deb74ad5a8 100644
--- a/net/quic/core/quic_stream_sequencer_buffer_test.cc
+++ b/net/quic/core/quic_stream_sequencer_buffer_test.cc
@@ -403,6 +403,10 @@ TEST_F(QuicStreamSequencerBufferTest, Readv100Bytes) {
   EXPECT_EQ(100u, buffer_->BytesConsumed());
   EXPECT_EQ(source, string(dest, read));
   EXPECT_EQ(1u, helper_->frame_arrival_time_map()->size());
+  if (FLAGS_quic_sequencer_buffer_retire_block_in_time) {
+    // The first block should be released as its data has been read out.
+    EXPECT_EQ(nullptr, helper_->GetBlock(0));
+  }
   EXPECT_TRUE(helper_->CheckBufferInvariants());
 }