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/update_attempter.h b/update_attempter.h
index 3c6f4a1..9e48179 100644
--- a/update_attempter.h
+++ b/update_attempter.h
@@ -141,7 +141,7 @@
                               UpdateAttemptFlags flags);
 
   // This is the version of CheckForUpdate called by AttemptInstall API.
-  virtual bool CheckForInstall(const std::vector<std::string>& dlc_module_ids,
+  virtual bool CheckForInstall(const std::vector<std::string>& dlc_ids,
                                const std::string& omaha_url);
 
   // This is the internal entry point for going through a rollback. This will
@@ -447,7 +447,7 @@
   int64_t GetPingMetadata(const PrefsInterface& prefs,
                           const std::string& metadata_name) const;
 
-  // Calculates the update parameters for DLCs. Sets the |dlc_modules_|
+  // Calculates the update parameters for DLCs. Sets the |dlc_ids_|
   // parameter on the |omaha_request_params_| object.
   void CalculateDlcParams();
 
@@ -555,7 +555,7 @@
   std::string forced_omaha_url_;
 
   // A list of DLC module IDs.
-  std::vector<std::string> dlc_module_ids_;
+  std::vector<std::string> dlc_ids_;
   // Whether the operation is install (write to the current slot not the
   // inactive slot).
   bool is_install_;