Implement Drain() on HttpPipelinedStream.

net/http/http_response_body_drainer.h

 // Copyright (c) 2011 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_RESPONSE_BODY_DRAINER_H_
 #define NET_HTTP_HTTP_RESPONSE_BODY_DRAINER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
@@ skipping 18 matching lines @@
   static const int kTimeoutInSeconds = 5;
 
   explicit HttpResponseBodyDrainer(HttpStream* stream);
   ~HttpResponseBodyDrainer();
 
   // Starts reading the body until completion, or we hit the buffer limit, or we
   // timeout.  After Start(), |this| will eventually delete itself.  If it
   // doesn't complete immediately, it will add itself to |session|.
   void Start(HttpNetworkSession* session);
 
+  // As above, but stop reading once |num_bytes_to_drain| has been reached.
+  void StartWithSize(HttpNetworkSession* session, int num_bytes_to_drain);
+
  private:
   enum State {
     STATE_DRAIN_RESPONSE_BODY,
     STATE_DRAIN_RESPONSE_BODY_COMPLETE,
     STATE_NONE,
   };
 
   int DoLoop(int result);
 
   int DoDrainResponseBody();
   int DoDrainResponseBodyComplete(int result);
 
   void OnIOComplete(int result);
   void OnTimerFired();
   void Finish(int result);
 
+  int read_size_;
   scoped_refptr<IOBuffer> read_buf_;
   const scoped_ptr<HttpStream> stream_;
   State next_state_;
   int total_read_;
   OldCompletionCallbackImpl<HttpResponseBodyDrainer> io_callback_;
   OldCompletionCallback* user_callback_;
   base::OneShotTimer<HttpResponseBodyDrainer> timer_;
   HttpNetworkSession* session_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpResponseBodyDrainer);
 };
 
 }  // namespace net
 
 #endif // NET_HTTP_HTTP_RESPONSE_BODY_DRAINER_H_