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

net/socket/tcp_socket_libevent.cc

Index: net/socket/tcp_socket_libevent.cc
diff --git a/net/socket/tcp_socket_libevent.cc b/net/socket/tcp_socket_libevent.cc
index a7022fd85745bbe57ba1127d66530a141964c428..72ae5809e106c6ba37c1f061d93d96e255c7dfb7 100644
--- a/net/socket/tcp_socket_libevent.cc
+++ b/net/socket/tcp_socket_libevent.cc
@@ -501,22 +501,18 @@ int TCPSocketLibevent::SetAddressReuse(bool allow) {
   return OK;
 }
 
-bool TCPSocketLibevent::SetReceiveBufferSize(int32 size) {
+int TCPSocketLibevent::SetReceiveBufferSize(int32 size) {
   DCHECK(CalledOnValidThread());
   int rv = setsockopt(socket_, SOL_SOCKET, SO_RCVBUF,
-      reinterpret_cast<const char*>(&size),
-      sizeof(size));
-  DCHECK(!rv) << "Could not set socket receive buffer size: " << errno;
-  return rv == 0;
+                      reinterpret_cast<const char*>(&size), sizeof(size));
+  return (rv == 0) ? OK : MapSystemError(errno);
 }
 
-bool TCPSocketLibevent::SetSendBufferSize(int32 size) {
+int TCPSocketLibevent::SetSendBufferSize(int32 size) {
   DCHECK(CalledOnValidThread());
   int rv = setsockopt(socket_, SOL_SOCKET, SO_SNDBUF,
-      reinterpret_cast<const char*>(&size),
-      sizeof(size));
-  DCHECK(!rv) << "Could not set socket send buffer size: " << errno;
-  return rv == 0;
+                      reinterpret_cast<const char*>(&size), sizeof(size));
+  return (rv == 0) ? OK : MapSystemError(errno);
 }
 
 bool TCPSocketLibevent::SetKeepAlive(bool enable, int delay) {