Add optional mandatory policy setting for template generation

grit/format/policy_templates/writers/reg_writer.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 
 import json
 
 from grit.format.policy_templates.writers import template_writer
 
@@ skipping 65 matching lines @@
         else:
           example_value_str = 'dword:00000000'
       elif policy['type'] in ('int', 'int-enum'):
         example_value_str = 'dword:%08x' % example_value
       else:
         raise Exception('unknown policy type %s:' % policy['type'])
 
       list.append('"%s"=%s' % (policy['name'], example_value_str))
 
   def WritePolicy(self, policy):
-    self._WritePolicy(policy,
-                      self.config['win_reg_mandatory_key_name'],
-                      self._mandatory)
+    if self.CanBeMandatory(policy):
+      self._WritePolicy(policy,
+                        self.config['win_reg_mandatory_key_name'],
+                        self._mandatory)
 
   def WriteRecommendedPolicy(self, policy):
     self._WritePolicy(policy,
                       self.config['win_reg_recommended_key_name'],
                       self._recommended)
 
   def BeginTemplate(self):
     pass
 
   def EndTemplate(self):
     pass
 
   def Init(self):
     self._mandatory = []
     self._recommended = []
     self._last_key = {}
 
   def GetTemplateText(self):
     prefix = ['Windows Registry Editor Version 5.00']
     all = prefix + self._mandatory + self._recommended
     return self.NEWLINE.join(all)