Allow substitution of messages as variables in other messages.

grit/format/js_map_format.py

Index: grit/format/js_map_format.py
diff --git a/grit/format/js_map_format.py b/grit/format/js_map_format.py
index 2eedbfbb5c780b39f3683560f25ee768cf084684..d17617982249f0810f23940807c4ae086e6ba866 100644
--- a/grit/format/js_map_format.py
+++ b/grit/format/js_map_format.py
@@ -18,13 +18,10 @@ from grit.node import io
 class TopLevel(interface.ItemFormatter):
   """Writes out the required preamble for JS files."""
 
-  def Format(self, item, lang='en', begin_item=True, output_dir='.'):
+  def Format(self, item, lang='en', output_dir='.'):
     """Format the JS file header."""
     assert isinstance(lang, types.StringTypes)
-    if not begin_item:
-      return ''
-    else:
-      return '''//  Copyright %d Google Inc. All Rights Reserved.
+    return '''//  Copyright %d Google Inc. All Rights Reserved.
 // This file is automatically generated by GRIT.  Do not edit.
 ''' % (util.GetCurrentYear())
 
@@ -32,21 +29,15 @@ class TopLevel(interface.ItemFormatter):
 class StringTable(interface.ItemFormatter):
   """Writes out the string table."""
 
-  def Format(self, item, lang='en', begin_item=True, output_dir='.'):
-    if begin_item:
-      return ''
-    else:
-      return '\n'
+  def FormatEnd(self, item, lang='en', output_dir='.'):
+    return '\n'
 
 
 class Message(interface.ItemFormatter):
   """Writes out a single message."""
 
-  def Format(self, item, lang='en', begin_item=True, output_dir='.'):
+  def Format(self, item, lang='en', output_dir='.'):
     """Format a single message."""
-    if not begin_item:
-      return ''
-
     from grit.node import message
 
     assert isinstance(lang, types.StringTypes)