buffet: Save save buffet state on UpdateDeviceInfo call

Buffet needs to save state as soon as possible when basic info is
updated. Save() call should be added by CL:266206.

BUG=brillo:377
TEST=FEATURES=test emerge-gizmo buffet

Change-Id: I38e620340d04ba2ae2e261c8d7af244c76910a01
Reviewed-on: https://chromium-review.googlesource.com/268684
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>

buffet/device_registration_info.cc

diff --git a/buffet/device_registration_info.cc b/buffet/device_registration_info.cc
index eec9985..136513d 100644
--- a/buffet/device_registration_info.cc
+++ b/buffet/device_registration_info.cc
@@ -767,6 +767,8 @@
   config_->set_description(description);
   config_->set_location(location);
 
+  Save();
+
   OnConfigChanged();
 
   if (HaveRegistrationCredentials(nullptr)) {

buffet/device_registration_info_unittest.cc

diff --git a/buffet/device_registration_info_unittest.cc b/buffet/device_registration_info_unittest.cc
index 6e3feb2..ee230ab 100644
--- a/buffet/device_registration_info_unittest.cc
+++ b/buffet/device_registration_info_unittest.cc
@@ -470,8 +470,7 @@
   std::string device_id = dev_reg_->RegisterDevice(params, nullptr);
 
   EXPECT_EQ(test_data::kDeviceId, device_id);
-  EXPECT_EQ(1,
-            storage_->save_count());  // The device info must have been saved.
+  EXPECT_GT(storage_->save_count(), 1);  // The state must have been saved.
   EXPECT_EQ(3, transport_->GetRequestCount());
   EXPECT_EQ(RegistrationStatus::kConnecting, dev_reg_->GetRegistrationStatus());