Treat 0 returned from HttpStream::ReadResponseBody correctly.

net/http/http_response_body_drainer.cc

 // 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.
 
 #include "net/http/http_response_body_drainer.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
@@ skipping 80 matching lines @@
       base::Bind(&HttpResponseBodyDrainer::OnIOComplete,
                  base::Unretained(this)));
 }
 
 int HttpResponseBodyDrainer::DoDrainResponseBodyComplete(int result) {
   DCHECK_NE(ERR_IO_PENDING, result);
 
   if (result < 0)
     return result;
 
-  if (result == 0)
-    return ERR_CONNECTION_CLOSED;
-
   total_read_ += result;
   if (stream_->IsResponseBodyComplete())
     return OK;
 
   DCHECK_LE(total_read_, kDrainBodyBufferSize);
   if (total_read_ >= kDrainBodyBufferSize)
     return ERR_RESPONSE_BODY_TOO_BIG_TO_DRAIN;
 
   next_state_ = STATE_DRAIN_RESPONSE_BODY;
   return OK;
@@ skipping 21 matching lines @@
     stream_->Close(true /* no keep-alive */);
   } else {
     DCHECK_EQ(OK, result);
     stream_->Close(false /* keep-alive */);
   }
 
   delete this;
 }
 
 }  // namespace net