buffet: Add read-only properties with buffet config options

Added OemName, ModelName, ModelId, Name, Description, Location buffet
properties.
Added UpdateDeviceInfo to allow changing of device Name, Description and
Location.

BUG=brillo:377
TEST=FEATURE=test emerge-gizmo buffet
     test_that -b $BOARD $DEV_HOST buffet_BasicDBusAPI
CQ-DEPEND=CL:266217

Change-Id: Id27f9a65194d4b7176196b599280fc4ada66eda2
Reviewed-on: https://chromium-review.googlesource.com/266206
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
diff --git a/buffet/device_registration_info_unittest.cc b/buffet/device_registration_info_unittest.cc
index 2f25d7a..7e09cfd 100644
--- a/buffet/device_registration_info_unittest.cc
+++ b/buffet/device_registration_info_unittest.cc
@@ -197,21 +197,14 @@
     config_store.SetString("service_url", test_data::kServiceURL);
     std::unique_ptr<BuffetConfig> config{new BuffetConfig};
     config->Load(config_store);
-    auto mock_callback = base::Bind(
-        &DeviceRegistrationInfoTest::OnRegistrationStatusChange,
-        base::Unretained(this));
     dev_reg_ = std::unique_ptr<DeviceRegistrationInfo>(
         new DeviceRegistrationInfo(command_manager_, state_manager_,
                                    std::move(config),
                                    transport_, storage_,
                                    true,
-                                   mock_callback));
-    EXPECT_CALL(*this, OnRegistrationStatusChange())
-        .Times(testing::AnyNumber());
+                                   nullptr));
   }
 
-  MOCK_METHOD0(OnRegistrationStatusChange, void());
-
   base::DictionaryValue data_;
   std::shared_ptr<MemStorage> storage_;
   std::shared_ptr<chromeos::http::fake::Transport> transport_;