Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/http2/hpack/decoder/hpack_whole_entry_buffer.h

 // Copyright 2016 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_HTTP2_HPACK_DECODER_HPACK_WHOLE_ENTRY_BUFFER_H_
 #define NET_HTTP2_HPACK_DECODER_HPACK_WHOLE_ENTRY_BUFFER_H_
 
 // HpackWholeEntryBuffer isolates a listener from the fact that an entry may
 // be split across multiple input buffers, providing one callback per entry.
 // HpackWholeEntryBuffer requires that the HpackEntryDecoderListener be made in
@@ skipping 42 matching lines @@
   // instances name_ and value_ are buffered, which allows any underlying
   // transport buffer to be freed or reused without overwriting the decoded
   // strings. This is needed only when an HPACK entry is split across transport
   // buffers. See HpackDecoder::DecodeFragment.
   void BufferStringsIfUnbuffered();
 
   // Was an error detected? After an error has been detected and reported,
   // no further callbacks will be made to the listener.
   bool error_detected() const { return error_detected_; }
 
+  // Returns the estimate of dynamically allocated memory in bytes.
+  size_t EstimateMemoryUsage() const;
+
   // Implement the HpackEntryDecoderListener methods.
 
   void OnIndexedHeader(size_t index) override;
   void OnStartLiteralHeader(HpackEntryType entry_type,
                             size_t maybe_name_index) override;
   void OnNameStart(bool huffman_encoded, size_t len) override;
   void OnNameData(const char* data, size_t len) override;
   void OnNameEnd() override;
   void OnValueStart(bool huffman_encoded, size_t len) override;
   void OnValueData(const char* data, size_t len) override;
@@ skipping 19 matching lines @@
   HpackEntryType entry_type_;
 
   bool error_detected_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(HpackWholeEntryBuffer);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP2_HPACK_DECODER_HPACK_WHOLE_ENTRY_BUFFER_H_