[BattOr] Retry battor_agent commands when they fail.

tools/battor_agent/battor_connection_impl.cc

 // Copyright 2015 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 "tools/battor_agent/battor_connection_impl.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
@@ skipping 62 matching lines @@
   if (!serial_log_path.empty()) {
     serial_log_.open(serial_log_path.c_str(),
                      std::fstream::out | std::fstream::trunc);
   }
 }
 
 BattOrConnectionImpl::~BattOrConnectionImpl() {}
 
 void BattOrConnectionImpl::Open() {
   if (io_handler_) {
+    // Opening new connection so flush serial data from old connection.
+    Flush();

[rnephew (Reviews Here), 2017/05/09 15:04:06]

Are the flushes not needed elsewhere because we moved it here?

[aschulman, 2017/05/11 13:13:00]

Correct. Before we had to flush manually between retries of specific messages
(e.g., INIT). Now when a command fails it will reopen the BattOr connection
which will then jump into this condition and Flush() the existing connection.

     OnOpened(true);
     return;
   }
 
   io_handler_ = CreateIoHandler();
 
   device::serial::ConnectionOptions options;
   options.bitrate = kBattOrBitrate;
   options.data_bits = kBattOrDataBits;
   options.parity_bit = kBattOrParityBit;
@@ skipping 259 matching lines @@
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE,
       base::Bind(&Listener::OnBytesSent, base::Unretained(listener_), success));
 }
 
 void BattOrConnectionImpl::LogSerial(const std::string& str) {
   serial_log_ << str << std::endl << std::endl;
 }
 
 }  // namespace battor