update_engine: Use GetDlcsToUpdate() instead of GetInstalled()

The meaning of GetInstalled() DBus in dlcservice have changed. So we need
to get the list of DLCs that ought to be updated from the new DBus
GetDlcsToUpdate().

Also rename all dlc_module_ids to dlc_ids.

BUG=chromium:1071654
TEST=cros_workon_make --board reef --test update_engine

Cq-Depend: chromium:2157669
Change-Id: I02e450a1fd75f8b387eb8a107c9c8a32f3e01e6e
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2163441
Tested-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Andrew Lassalle <andrewlassalle@chromium.org>
Reviewed-by: Jae Hoon Kim <kimjae@chromium.org>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
diff --git a/common_service.cc b/common_service.cc
index 347833b..85fb9e4 100644
--- a/common_service.cc
+++ b/common_service.cc
@@ -105,9 +105,8 @@
 
 bool UpdateEngineService::AttemptInstall(brillo::ErrorPtr* error,
                                          const string& omaha_url,
-                                         const vector<string>& dlc_module_ids) {
-  if (!system_state_->update_attempter()->CheckForInstall(dlc_module_ids,
-                                                          omaha_url)) {
+                                         const vector<string>& dlc_ids) {
+  if (!system_state_->update_attempter()->CheckForInstall(dlc_ids, omaha_url)) {
     // TODO(xiaochu): support more detailed error messages.
     LogAndSetError(error, FROM_HERE, "Could not schedule install operation.");
     return false;