Implement break signal for serial api.

device/serial/serial_io_handler_posix.cc

 // Copyright 2014 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 "device/serial/serial_io_handler_posix.h"
 
 #include <sys/ioctl.h>
 #include <termios.h>
 
 #include "base/posix/eintr_wrapper.h"
@@ skipping 454 matching lines @@
                                                  : serial::PARITY_BIT_EVEN;
   } else {
     info->parity_bit = serial::PARITY_BIT_NO;
   }
   info->stop_bits =
       (config.c_cflag & CSTOPB) ? serial::STOP_BITS_TWO : serial::STOP_BITS_ONE;
   info->cts_flow_control = (config.c_cflag & CRTSCTS) != 0;
   return info.Pass();
 }
 
+bool SerialIoHandlerPosix::SetBreak() {
+  return ioctl(file().GetPlatformFile(), TIOCSBRK, 0) == 0;

[Reilly Grant (use Gerrit), 2015/06/10 19:42:13]

Please catch errors here and use a VPLOG to record them.

[limasdf, 2015/06/11 22:14:24]

Done.

+}
+
+bool SerialIoHandlerPosix::ClearBreak() {
+  return ioctl(file().GetPlatformFile(), TIOCCBRK, 0) == 0;

[Reilly Grant (use Gerrit), 2015/06/10 19:42:13]

Same here.

[limasdf, 2015/06/11 22:14:23]

Done.

+}
+
 std::string SerialIoHandler::MaybeFixUpPortName(const std::string& port_name) {
   return port_name;
 }
 
 }  // namespace device