[BattOr] Make BattOr able to return firmware version.

tools/battor_agent/battor_agent.h

Index: tools/battor_agent/battor_agent.h
diff --git a/tools/battor_agent/battor_agent.h b/tools/battor_agent/battor_agent.h
index 810df26936af2cf15d4c72845937aa7fac8da676..cc3a7c36139e9961e4c5c5ed0a4d69ef47684674 100644
--- a/tools/battor_agent/battor_agent.h
+++ b/tools/battor_agent/battor_agent.h
@@ -43,6 +43,8 @@ class BattOrAgent : public BattOrConnection::Listener,
     virtual void OnStopTracingComplete(const std::string& trace,
                                        BattOrError error) = 0;
     virtual void OnRecordClockSyncMarkerComplete(BattOrError error) = 0;
+    virtual void OnGetFirmwareGitHashComplete(const std::string& version,
+                                              BattOrError error) = 0;
   };
 
   BattOrAgent(
@@ -55,6 +57,7 @@ class BattOrAgent : public BattOrConnection::Listener,
   void StartTracing();
   void StopTracing();
   void RecordClockSyncMarker(const std::string& marker);
+  void GetFirmwareGitHash();
 
   // Returns whether the BattOr is able to record clock sync markers in its own
   // trace log.
@@ -85,6 +88,7 @@ class BattOrAgent : public BattOrConnection::Listener,
     START_TRACING,
     STOP_TRACING,
     RECORD_CLOCK_SYNC_MARKER,
+    GET_FIRMWARE_GIT_HASH,
   };
 
   enum class Action {
@@ -111,6 +115,10 @@ class BattOrAgent : public BattOrConnection::Listener,
     // Actions required for recording a clock sync marker.
     SEND_CURRENT_SAMPLE_REQUEST,
     READ_CURRENT_SAMPLE,
+
+    // Actions required for returning firmware git hash.
+    SEND_GIT_HASH_REQUEST,
+    READ_GIT_HASH,
   };
 
   // Performs an action.
@@ -181,6 +189,9 @@ class BattOrAgent : public BattOrConnection::Listener,
   // 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);
 };