Use ControlInterface for creating proxies

This removes the IPC specific (D-Bus) dependencies from FirewallManager
and ShillManager.

Bug: 24194427
TEST=Verify wifi bootstrapping on both dragonboard (Android) and wolf
TEST=(Chrome OS)

Change-Id: Iac3b91300f938e8080d6ab4513fe84dea2880693
diff --git a/daemon.h b/daemon.h
index 137adaa..38869fd 100644
--- a/daemon.h
+++ b/daemon.h
@@ -20,6 +20,7 @@
 #include <base/callback_forward.h>
 #include <brillo/daemons/dbus_daemon.h>
 
+#include "apmanager/control_interface.h"
 #include "apmanager/manager.h"
 
 namespace apmanager {
@@ -42,6 +43,7 @@
  private:
   friend class DaemonTest;
 
+  std::unique_ptr<ControlInterface> control_interface_;
   std::unique_ptr<Manager> manager_;
   base::Closure startup_callback_;