net: Introduce SeekableIOBuffer and clean up HttpStreamParser.

net/http/http_stream_parser.h

 // Copyright (c) 2012 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_HTTP_HTTP_STREAM_PARSER_H_
 #define NET_HTTP_HTTP_STREAM_PARSER_H_
 #pragma once
 
 #include <string>
 
@@ skipping 84 matching lines @@
   // Returns true if request headers and body should be merged (i.e. the
   // sum is small enough and the body is in memory, and not chunked).
   static bool ShouldMergeRequestHeadersAndBody(
       const std::string& request_headers,
       const UploadDataStream* request_body);
 
   // The number of extra bytes required to encode a chunk.
   static const size_t kChunkHeaderFooterSize;
 
  private:
+  class SeekableIOBuffer;
+
   // FOO_COMPLETE states implement the second half of potentially asynchronous
   // operations and don't necessarily mean that FOO is complete.
   enum State {
     STATE_NONE,
     STATE_SENDING_HEADERS,
     // If the request comes with a body, either of the following two
     // states will be executed, depending on whether the body is chunked
     // or not.
     STATE_SENDING_CHUNKED_BODY,
     STATE_SENDING_NON_CHUNKED_BODY,
@@ skipping 101 matching lines @@
   // The underlying socket.
   ClientSocketHandle* const connection_;
 
   BoundNetLog net_log_;
 
   // Callback to be used when doing IO.
   CompletionCallback io_callback_;
 
   // Stores an encoded chunk for chunked uploads.
   // Note: This should perhaps be improved to not create copies of the data.
-  scoped_refptr<IOBufferWithSize> raw_chunk_buf_;
-  // Wraps raw_chunk_buf_ to read the remaining data progressively.
-  scoped_refptr<DrainableIOBuffer> chunk_buf_;
+  scoped_refptr<SeekableIOBuffer> chunk_buf_;
   size_t chunk_length_without_encoding_;
   bool sent_last_chunk_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpStreamParser);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_STREAM_PARSER_H_