[BattOr] Add flushing before requesting firmware git hash.

tools/battor_agent/battor_agent.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_agent.h"
 
 #include <iomanip>
 
 #include "base/bind.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "tools/battor_agent/battor_connection_impl.h"
@@ skipping 499 matching lines @@
 
     // The following actions are required for RecordClockSyncMarker:
     case Action::SEND_CURRENT_SAMPLE_REQUEST:
       SendControlMessage(BATTOR_CONTROL_MESSAGE_TYPE_READ_SAMPLE_COUNT, 0, 0);
       return;
     case Action::READ_CURRENT_SAMPLE:
       connection_->ReadMessage(BATTOR_MESSAGE_TYPE_CONTROL_ACK);
       return;
 
     case Action::SEND_GIT_HASH_REQUEST:
+      connection_->Flush();
       SendControlMessage(
           BATTOR_CONTROL_MESSAGE_TYPE_GET_FIRMWARE_GIT_HASH, 0, 0);
       return;
 
     case Action::READ_GIT_HASH:
       connection_->ReadMessage(BATTOR_MESSAGE_TYPE_CONTROL_ACK);
       return;
 
     case Action::INVALID:
       NOTREACHED();
@@ skipping 121 matching lines @@
     if (clock_sync_marker != clock_sync_markers_.end())
       trace_stream << " <" << clock_sync_marker->second << ">";
 
     trace_stream << std::endl;
   }
 
   return trace_stream.str();
 }
 
 }  // namespace battor