update_engine: Move DLC metadata ownership to update_engine

Add dbus messages so dlcservice can let update_engine know when a DLC is
installed or uninstalled.

BUG=chromium:912666
TEST=unittests, install and uninstall DLCs on DUT.

Cq-Depend: chromium:2112994,chromium:2113254
Change-Id: I35374504afcdaf96b099e343cabe072fc18f1022
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2113134
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Jae Hoon Kim <kimjae@chromium.org>
Tested-by: Andrew Lassalle <andrewlassalle@chromium.org>
Commit-Queue: Andrew Lassalle <andrewlassalle@chromium.org>
diff --git a/dbus_bindings/org.chromium.UpdateEngineInterface.dbus-xml b/dbus_bindings/org.chromium.UpdateEngineInterface.dbus-xml
index afa34d7..51457e5 100644
--- a/dbus_bindings/org.chromium.UpdateEngineInterface.dbus-xml
+++ b/dbus_bindings/org.chromium.UpdateEngineInterface.dbus-xml
@@ -51,6 +51,18 @@
     </method>
     <method name="ResetStatus">
     </method>
+    <method name="SetDlcActiveValue">
+      <arg type="b" name="is_active" direction="in">
+        <tp:docstring>
+          If the DLC is being set to active or inactive.
+        </tp:docstring>
+      </arg>
+      <arg type="s" name="dlc_id" direction="in">
+        <tp:docstring>
+          The ID of the DLC module that will be set to active/inactive.
+        </tp:docstring>
+      </arg>
+    </method>
     <method name="GetStatusAdvanced">
       <arg type="ay" name="status" direction="out">
         <tp:docstring>