Adding new method required in Gingerbread.

MyTracksTest/src/com/google/android/apps/mytracks/io/backup/PreferenceBackupHelperTest.java

@@ -38,7 +38,7 @@ public class PreferenceBackupHelperTest extends TestCase {
    */
   private class MockPreferenceEditor implements SharedPreferences.Editor {
     private Map<String, Object> newPreferences = new HashMap<String, Object>(preferenceValues);
-    
+
     @Override
     public Editor clear() {
       newPreferences.clear();
@@ -51,6 +51,11 @@ public class PreferenceBackupHelperTest extends TestCase {
       return true;
     }
 
+    @Override
+    public void apply() {
+      commit();
+    }
+
     @Override
     public Editor putBoolean(String key, boolean value) {
       return put(key, value);