make SetReceiveBufferSize and SetSendBufferSize return net error codes (instead of bools)

net/base/net_errors.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/base/net_errors.h"
 
 #include "base/basictypes.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/stringize_macros.h"
 
@@ skipping 41 matching lines @@
       return net::ERR_ACCESS_DENIED;
     case base::File::FILE_ERROR_INVALID_URL:
       return net::ERR_INVALID_URL;
     case base::File::FILE_ERROR_NOT_FOUND:
       return net::ERR_FILE_NOT_FOUND;
     default:
       return net::ERR_FAILED;
   }
 }
 
+int MapSystemErrorWithDefault(int os_error, int default_net_error) {
+  int net_error = MapSystemError(os_error);
+  if (net_error != OK)
+    return net_error;
+  DLOG(WARNING)  << "OS Error was not set meaningfully " << os_error;

[wtc, 2014/04/09 15:34:49]

Hmm... the problem with this error message is that it doesn't have a context.
Here are some ideas to provide a context.

1. Also log default_net_error.

2. Add a "failed_function_name" argument to the function.

3. Dump a call stack.

Nit: "meaningfully" seems superfluous. "Error" doesn't need to be capitalized.

+  DCHECK_NE(default_net_error, OK);

[wtc, 2014/04/09 15:34:49]

This DCHECK should be at the beginning of the function, so that it is always
executed.

+  return default_net_error;
+}
+
 }  // namespace net