This QUIC change includes:

net/quic/core/quic_headers_stream.h

Index: net/quic/core/quic_headers_stream.h
diff --git a/net/quic/core/quic_headers_stream.h b/net/quic/core/quic_headers_stream.h
index b28a7a45a7c368c84b2cea31c00cd09f5e9340e6..f74b869693cdeba24dd03905d4d44ba9c3b62b87 100644
--- a/net/quic/core/quic_headers_stream.h
+++ b/net/quic/core/quic_headers_stream.h
@@ -6,6 +6,7 @@
 #define NET_QUIC_CORE_QUIC_HEADERS_STREAM_H_
 
 #include <cstddef>
+#include <deque>
 #include <memory>
 
 #include "base/macros.h"
@@ -37,14 +38,53 @@ class QUIC_EXPORT_PRIVATE QuicHeadersStream : public QuicStream {
   // Release underlying buffer if allowed.
   void MaybeReleaseSequencerBuffer();
 
+  void OnStreamFrameAcked(const QuicStreamFrame& frame,
+                          QuicTime::Delta ack_delay_time) override;
+
+  void OnStreamFrameRetransmitted(const QuicStreamFrame& frame) override;
+
  private:
   friend class test::QuicHeadersStreamPeer;
 
+  // Override to store mapping from offset, length to ack_listener. This
+  // ack_listener is notified once data within [offset, offset + length] is
+  // acked or retransmitted.
+  QuicConsumedData WritevDataInner(
+      QuicIOVector iov,
+      QuicStreamOffset offset,
+      bool fin,
+      QuicReferenceCountedPointer<QuicAckListenerInterface> ack_listener)
+      override;
+
+  // CompressedHeaderInfo includes simple information of a header, including
+  // offset in headers stream, unacked length and ack listener of this header.
+  struct QUIC_EXPORT_PRIVATE CompressedHeaderInfo {
+    CompressedHeaderInfo(
+        QuicStreamOffset headers_stream_offset,
+        QuicStreamOffset full_length,
+        QuicReferenceCountedPointer<QuicAckListenerInterface> ack_listener);
+    CompressedHeaderInfo(const CompressedHeaderInfo& other);
+    ~CompressedHeaderInfo();
+
+    // Offset the header was sent on the headers stream.
+    QuicStreamOffset headers_stream_offset;
+    // The full length of the header.
+    QuicByteCount full_length;
+    // The remaining bytes to be acked.
+    QuicByteCount unacked_length;
+    // Ack listener of this header, and it is notified once any of the bytes has
+    // been acked or retransmitted.
+    QuicReferenceCountedPointer<QuicAckListenerInterface> ack_listener;
+  };
+
   // Returns true if the session is still connected.
   bool IsConnected();
 
   QuicSpdySession* spdy_session_;
 
+  // Headers that have not been fully acked.
+  std::deque<CompressedHeaderInfo> unacked_headers_;
+
   DISALLOW_COPY_AND_ASSIGN(QuicHeadersStream);
 };