dbus: transition to interface for testing

To make testing easier, the dbus objects now receive a
helper interface to use instead of calling into a helper module.

Tested: Ran on quanta-q71l board and it behaved as expected.

Change-Id: I2521d9c75aec76e92d2e26dc044d01011e44d552
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/dbus/dbusactiveread.hpp b/dbus/dbusactiveread.hpp
index a9146b9..85380fb 100644
--- a/dbus/dbusactiveread.hpp
+++ b/dbus/dbusactiveread.hpp
@@ -1,13 +1,12 @@
 #pragma once
 
 #include <memory>
+#include <sdbusplus/bus.hpp>
 #include <string>
 
-#include <sdbusplus/bus.hpp>
-
+#include "dbus/util.hpp"
 #include "interfaces.hpp"
 
-
 /*
  * This ReadInterface will actively reach out over dbus upon calling read to
  * get the value from whomever owns the associated dbus path.
@@ -17,11 +16,13 @@
     public:
         DbusActiveRead(sdbusplus::bus::bus& bus,
                        const std::string& path,
-                       const std::string& service)
+                       const std::string& service,
+                       DbusHelperInterface *helper)
             : ReadInterface(),
               _bus(bus),
               _path(path),
-              _service(service)
+              _service(service),
+              _helper(helper)
         { }
 
         ReadReturn read(void) override;
@@ -30,4 +31,5 @@
         sdbusplus::bus::bus& _bus;
         const std::string _path;
         const std::string _service; // the sensor service.
+        DbusHelperInterface *_helper;
 };