Experimenting with rjsmin in grit.

grit/format/data_pack.py

Index: grit/format/data_pack.py
diff --git a/grit/format/data_pack.py b/grit/format/data_pack.py
index 02616c39d40443d1c583f3acb351c7708f13ec54..9f85bb025eac66b478f711d748eb33047aa2a721 100755
--- a/grit/format/data_pack.py
+++ b/grit/format/data_pack.py
@@ -7,6 +7,11 @@
 files.
 """
 
+import os
+import sys
+
+import rjsmin
+
 import collections
 import exceptions
 import os
@@ -43,6 +48,17 @@ def Format(root, lang='en', output_dir='.'):
       if isinstance(node, (include.IncludeNode, message.MessageNode,
                            structure.StructureNode)):
         id, value = node.GetDataPackPair(lang, UTF8)
+        txt_id = node.GetTextualIds()[0]
+
+        # Use rjsmin to compress JavaScript resources. Closure would
+        # be even better but is tricky to integrate into the build
+        # system since it is Java.
+        if "_JS" in txt_id[-3:]:
+          size = len(value)
+          packed_value = rjsmin.jsmin(value)
+          packed_size = len(packed_value)
+          if packed_size < size:
+            value = packed_value
         if value is not None:
           data[id] = value
   return WriteDataPackToString(data, UTF8)