Update trim_data to deal with locale fallback failure for unit

source/data/translit/root_subset.txt

 // **************************************************************************
 // *  Copyright (C) 2004-2013, International Business Machine
 // *  Corporation; Unicode, Inc.; and others.  All Rights Reserved.
 // *
 // ***************************************************************************
 // This file specifies transliteration rulesets that are to be kept for Chromium
 // releases.
 //
 // Currently no rule sets in use.
+// Note that RuleBasedTransliteratorIDs block has to be present. Otherwise,
+// built-in transforms such as NFD/NFC would fail.
 
-root { }
+root {
+    RuleBasedTransliteratorIDs {
+    }
+}