Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/http2/hpack/decoder/hpack_whole_entry_buffer.h

Index: net/http2/hpack/decoder/hpack_whole_entry_buffer.h
diff --git a/net/http2/hpack/decoder/hpack_whole_entry_buffer.h b/net/http2/hpack/decoder/hpack_whole_entry_buffer.h
index 8ab5d693285a0cba201e5adefac052d776546745..d7f7e843b67560c60b53a6a92bf833d5d1bea39f 100644
--- a/net/http2/hpack/decoder/hpack_whole_entry_buffer.h
+++ b/net/http2/hpack/decoder/hpack_whole_entry_buffer.h
@@ -60,6 +60,9 @@ class NET_EXPORT_PRIVATE HpackWholeEntryBuffer
   // 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;