[libgames-support] scores: Allow creating a DirectoryImporter with no CategoryConvertFunc

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 3808d56f6ffb4e26f4b06d259fd4ff4acd66175d
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Sat Feb 13 21:13:24 2016 -0600

    scores: Allow creating a DirectoryImporter with no CategoryConvertFunc
    
    Turns out, most games will not want to rename their categories... this
    API was too Nibbles-specific.

 games/scores/directory-importer.vala |   10 ++++++++--
 tests/test-scores.vala               |    2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)
---
diff --git a/games/scores/directory-importer.vala b/games/scores/directory-importer.vala
index 68a5100..c4450eb 100644
--- a/games/scores/directory-importer.vala
+++ b/games/scores/directory-importer.vala
@@ -36,9 +36,15 @@ public class DirectoryImporter : Importer
      * directory, and some of those files might not be valid categories.
      */
     public delegate string? CategoryConvertFunc (string old_key);
-    private CategoryConvertFunc category_convert;
+    private CategoryConvertFunc? category_convert;
 
-    public DirectoryImporter (CategoryConvertFunc category_convert)
+    public DirectoryImporter ()
+    {
+        /* Default converter for games that don't require category migration. */
+        this.category_convert = ((old_key) => { return old_key; });
+    }
+
+    public DirectoryImporter.with_convert_func (CategoryConvertFunc? category_convert)
     {
         this.category_convert = category_convert;
     }
diff --git a/tests/test-scores.vala b/tests/test-scores.vala
index 321c1a1..17ce65f 100644
--- a/tests/test-scores.vala
+++ b/tests/test-scores.vala
@@ -185,7 +185,7 @@ private void test_import_from_score_directory ()
                 return category;
             },
             Games.Scores.Style.PLAIN_DESCENDING,
-            new Games.Scores.DirectoryImporter ((old_key) => {
+            new Games.Scores.DirectoryImporter.with_convert_func ((old_key) => {
                 assert (old_key == "old-cat");
                 return "new-cat";
             }));