Make the BattOr agent retry start tracing when we fail to read an ack

tools/battor_agent/battor_agent.h

 // 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.
 
 #ifndef TOOLS_BATTOR_AGENT_BATTOR_AGENT_H_
 #define TOOLS_BATTOR_AGENT_BATTOR_AGENT_H_
 
 #include <map>
 
 #include "base/cancelable_callback.h"
@@ skipping 165 matching lines @@
   // The actual data samples recorded.
   std::vector<RawBattOrSample> samples_;
 
   // The expected sequence number of the next frame. We use this to ensure that
   // we receive frames in order.
   uint32_t next_sequence_number_;
 
   // The number of times we've attempted to init the BattOr.
   uint8_t num_init_attempts_;
 
+  // The number of times we've attempted the BattOr StartTracing command.
+  uint8_t num_start_tracing_attempts_;
+
   // The number of times that we've attempted to read the last message.
   uint8_t num_read_attempts_;
 
   // The timeout that's run when an action times out.
   base::CancelableClosure timeout_callback_;
 
   // The git hash of the BattOr firmware.
   std::string firmware_git_hash_;
 
   DISALLOW_COPY_AND_ASSIGN(BattOrAgent);
 };
 
 }  // namespace battor
 
 #endif  // TOOLS_BATTOR_AGENT_BATTOR_AGENT_H_