Release read buffer of QuicCryptoStream when incoming message become less frequent. Protected by --…

net/quic/core/quic_stream_sequencer.cc

Index: net/quic/core/quic_stream_sequencer.cc
diff --git a/net/quic/core/quic_stream_sequencer.cc b/net/quic/core/quic_stream_sequencer.cc
index 45f1e88ca7e4830f3c4bab0e7fc8a6b66ca8db69..597244b5436ddef4c2184922947d3699c593c89c 100644
--- a/net/quic/core/quic_stream_sequencer.cc
+++ b/net/quic/core/quic_stream_sequencer.cc
@@ -197,6 +197,12 @@ void QuicStreamSequencer::ReleaseBuffer() {
   buffered_frames_.ReleaseWholeBuffer();
 }
 
+void QuicStreamSequencer::ReleaseBufferIfEmpty() {
+  if (FLAGS_quic_release_crypto_stream_buffer && buffered_frames_.Empty()) {
+    buffered_frames_.ReleaseWholeBuffer();
+  }
+}
+
 void QuicStreamSequencer::FlushBufferedFrames() {
   DCHECK(ignore_read_data_);
   size_t bytes_flushed = buffered_frames_.FlushBufferedFrames();