Only generate grit header id values for messages that are

tools/grit/grit/node/message.py

Index: tools/grit/grit/node/message.py
diff --git a/tools/grit/grit/node/message.py b/tools/grit/grit/node/message.py
index 9410f93b899506254e5ba06527ba39c7d35333b0..8cdf0efa39d5420062b07c3fc9d7a69e49eea885 100644
--- a/tools/grit/grit/node/message.py
+++ b/tools/grit/grit/node/message.py
@@ -99,12 +99,15 @@ class MessageNode(base.ContentNode):
     return self.attrs['translateable'] == 'true'
 
   def ItemFormatter(self, t):
+    # Only generate an output if the if condition is satisfied.
+    if not self.SatisfiesOutputCondition():
+      return super(type(self), self).ItemFormatter(t)
+
     if t == 'rc_header':
       return grit.format.rc_header.Item()
-    elif (t in ['rc_all', 'rc_translateable', 'rc_nontranslateable'] and
-          self.SatisfiesOutputCondition()):
+    elif t in ('rc_all', 'rc_translateable', 'rc_nontranslateable'):
       return grit.format.rc.Message()
-    elif t == 'js_map_format' and self.SatisfiesOutputCondition():
+    elif t == 'js_map_format':
         return grit.format.js_map_format.Message()
     else:
       return super(type(self), self).ItemFormatter(t)