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

net/base/net_errors.h

Index: net/base/net_errors.h
diff --git a/net/base/net_errors.h b/net/base/net_errors.h
index 2c513612209f7c2eb08dc6c249160da506664b6f..cc83c7110a0267b0f0d4684b3edea7ffa6d8b3b0 100644
--- a/net/base/net_errors.h
+++ b/net/base/net_errors.h
@@ -57,6 +57,13 @@ NET_EXPORT std::vector<int> GetAllErrorCodesForUma();
 // A convenient function to translate file error to net error code.
 NET_EXPORT Error FileErrorToNetError(base::File::Error file_error);
 
+// Return a net_error other than net::OK, based on |os_error|.
+// Some older OSs (Mac 10.6?) may fail to set the os_error properly, even when
+// a system function returns a failing value.  This function is used to map such
+// cases into a default net_error, if the net_error would otherwise mistakenly
+// report OK (such as when errno was zero).
+int MapSystemErrorWithDefault(int os_error, int default_net_error);

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

Nit: please list this function right below the closely related MapSystemError.

+
 }  // namespace net
 
 #endif  // NET_BASE_NET_ERRORS_H__