HPACK optimal Huffman code instrumentation and UMA collection.

net/spdy/hpack_encoder.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_ENCODER_H_
 #define NET_SPDY_HPACK_ENCODER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 17 matching lines @@
   friend class test::HpackEncoderPeer;
 
   explicit HpackEncoder();
   ~HpackEncoder();
 
   // Encodes the given header set into the given string. Returns
   // whether or not the encoding was successful.
   bool EncodeHeaderSet(const std::map<std::string, std::string>& header_set,
                        std::string* output);
 
+  // Sets externally-owned storage for aggregating character counts of emitted
+  // literal representations.
+  void SetCharCountsStorage(std::vector<size_t>* char_counts,
+                            size_t* total_char_counts);
+
  private:
   static void CookieToCrumbs(base::StringPiece cookie,
                              std::vector<base::StringPiece>* out);
 
+  void UpdateCharacterCounts(base::StringPiece str);
+
   uint32 max_string_literal_size_;
   HpackEncodingContext context_;
 
+  // Externally-owned, nullable storage for character counts of literals.
+  std::vector<size_t>* char_counts_;
+  size_t* total_char_counts_;
+
   DISALLOW_COPY_AND_ASSIGN(HpackEncoder);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_HPACK_ENCODER_H_