buffet: Make RegisterDevice accept only ticket ID

Changing name, description and location is possible using
UpdateDeviceInfo.

BUG=none
TEST='FEATURES=test emerge-gizmo buffet'
CQ-DEPEND=CL:*216413,CL:271616

Change-Id: Ieed8b8537184e0dada9c36551ee7502bd50259f4
Reviewed-on: https://chromium-review.googlesource.com/271377
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
diff --git a/buffet/buffet_client.cc b/buffet/buffet_client.cc
index a874ec0..ef4bf03 100644
--- a/buffet/buffet_client.cc
+++ b/buffet/buffet_client.cc
@@ -313,17 +313,18 @@
 
   void CallRegisterDevice(const std::string& args,
                           ManagerProxy* manager_proxy) {
-    chromeos::VariantDictionary params;
+    std::string ticket_id;
     if (!args.empty()) {
       auto key_values = chromeos::data_encoding::WebParamsDecode(args);
       for (const auto& pair : key_values) {
-        params.insert(std::make_pair(pair.first, chromeos::Any(pair.second)));
+        if (pair.first == "ticket_id")
+          ticket_id = pair.second;
       }
     }
 
     ErrorPtr error;
     std::string device_id;
-    if (!manager_proxy->RegisterDevice(params, &device_id, &error)) {
+    if (!manager_proxy->RegisterDevice(ticket_id, &device_id, &error)) {
       return ReportError(error.get());
     }
 
@@ -380,8 +381,8 @@
   }
 
   void CallSetCommandVisibility(const std::string& command_list,
-                                    const std::string& visibility,
-                                    ManagerProxy* manager_proxy) {
+                                const std::string& visibility,
+                                ManagerProxy* manager_proxy) {
     ErrorPtr error;
     std::vector<std::string> commands =
         chromeos::string_utils::Split(command_list, ",", true, true);