QUIC - add instrumentation to HPACK.

net/spdy/hpack/hpack_decoder.h

 // 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.
 
 #ifndef NET_SPDY_HPACK_DECODER_H_
 #define NET_SPDY_HPACK_DECODER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 55 matching lines @@
   // header (which has been incrementally reconstructed) and notify
   // the visitor that the block is finished.
   bool HandleControlFrameHeadersComplete(size_t* compressed_len);
 
   // Accessor for the most recently decoded headers block. Valid until the next
   // call to HandleControlFrameHeadersData().
   // TODO(birenroy): Remove this method when all users of HpackDecoder specify
   // a SpdyHeadersHandlerInterface.
   const SpdyHeaderBlock& decoded_block() { return decoded_block_; }
 
+  void SetHeaderTableDebugVisitor(
+      std::unique_ptr<HpackHeaderTable::DebugVisitorInterface> visitor) {
+    header_table_.set_debug_visitor(std::move(visitor));
+  }
+
  private:
   // Adds the header representation to |decoded_block_|, applying the
   // following rules:
   //  - Multiple values of the Cookie header are joined, delmited by '; '.
   //    This reconstruction is required to properly handle Cookie crumbling
   //    (as per section 8.1.2.5 in RFC 7540).
   //  - Multiple values of other headers are joined and delimited by '\0'.
   //    Note that this may be too accomodating, as the sender's HTTP2 layer
   //    should have already joined and delimited these values.
   //
@@ skipping 45 matching lines @@
   bool DecodeNextStringLiteral(HpackInputStream* input_stream,
                                bool is_header_key,  // As distinct from a value.
                                base::StringPiece* output);
 
   DISALLOW_COPY_AND_ASSIGN(HpackDecoder);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_HPACK_DECODER_H_