Add preparer for overlay pre-singleton registration

It appears as though this is the first pre-singleton type to actually
be registered with the InitRegistrationContext as it failed due to an
uninitialized map, so this change also fixes that.

Bug: 182885307
Test: m nothing
Change-Id: Ibbf6d0db5f3c2fcc89291a16aa5f16b8b5009bd3
diff --git a/java/android_resources.go b/java/android_resources.go
index 4d420cf..6864ebb 100644
--- a/java/android_resources.go
+++ b/java/android_resources.go
@@ -22,8 +22,11 @@
 )
 
 func init() {
-	android.RegisterPreSingletonType("overlay", OverlaySingletonFactory)
+	registerOverlayBuildComponents(android.InitRegistrationContext)
+}
 
+func registerOverlayBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterPreSingletonType("overlay", OverlaySingletonFactory)
 }
 
 var androidResourceIgnoreFilenames = []string{