update_engine: Use org.chromium.KioskAppService service.

Make update_engine use the org.chromium.KioskAppService
D-Bus service exported by Chrome rather than the old methods
under org.chromium.LibCrosService.

BUG=chromium:703229
TEST=unit tests pass; also hacked up RealSystemProvider to
     call its GetKioskAppRequiredPlatformVersion and
     manually verified that the D-Bus call succeeds

Change-Id: I02d503da1e1aec2319c75e2237c87bfcdcd1f7e5
Reviewed-on: https://chromium-review.googlesource.com/987325
Commit-Ready: Dan Erat <derat@chromium.org>
Tested-by: Dan Erat <derat@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
diff --git a/update_manager/state_factory.h b/update_manager/state_factory.h
index 689684a..1c1c1d9 100644
--- a/update_manager/state_factory.h
+++ b/update_manager/state_factory.h
@@ -22,7 +22,7 @@
 
 namespace org {
 namespace chromium {
-class LibCrosServiceInterfaceProxyInterface;
+class KioskAppServiceInterfaceProxyInterface;
 }  // namespace chromium
 }  // namespace org
 
@@ -35,7 +35,7 @@
 // to initialize.
 State* DefaultStateFactory(
     policy::PolicyProvider* policy_provider,
-    org::chromium::LibCrosServiceInterfaceProxyInterface* libcros_proxy,
+    org::chromium::KioskAppServiceInterfaceProxyInterface* kiosk_app_proxy,
     chromeos_update_engine::SystemState* system_state);
 
 }  // namespace chromeos_update_manager