Make Quic client more memory efficient. Protected by --quic_headers_stream_release_sequencer_buffer.

net/quic/core/quic_client_session_base.cc

 // Copyright 2014 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/core/quic_client_session_base.h"
 
 #include "net/quic/core/quic_client_promised_info.h"
 #include "net/quic/core/quic_flags.h"
 #include "net/quic/core/spdy_utils.h"
 
@@ skipping 170 matching lines @@
     return static_cast<QuicSpdyStream*>(it->second.get());
   }
   return nullptr;
 }
 
 void QuicClientSessionBase::DeletePromised(QuicClientPromisedInfo* promised) {
   push_promise_index_->promised_by_url()->erase(promised->url());
   // Since promised_by_id_ contains the unique_ptr, this will destroy
   // promised.
   promised_by_id_.erase(promised->id());
+  headers_stream()->MaybeReleaseSequencerBuffer();
 }
 
 void QuicClientSessionBase::OnPushStreamTimedOut(QuicStreamId stream_id) {}
 
 void QuicClientSessionBase::ResetPromised(QuicStreamId id,
                                           QuicRstStreamErrorCode error_code) {
   SendRstStream(id, error_code, 0);
   if (!IsOpenStream(id)) {
     MaybeIncreaseLargestPeerStreamId(id);
     InsertLocallyClosedStreamsHighestOffset(id, 0);
   }
 }
 
+void QuicClientSessionBase::CloseStreamInner(QuicStreamId stream_id,
+                                             bool locally_reset) {
+  QuicSpdySession::CloseStreamInner(stream_id, locally_reset);
+  headers_stream()->MaybeReleaseSequencerBuffer();
+}
+
+bool QuicClientSessionBase::ShouldReleaseHeadersStreamSequencerBuffer() {
+  return num_active_requests() == 0 && promised_by_id_.empty();
+}
+
 }  // namespace net