Fix crashes in components/policy/resources/PRESUBMIT.py.

components/policy/resources/PRESUBMIT.py

Index: components/policy/resources/PRESUBMIT.py
diff --git a/components/policy/resources/PRESUBMIT.py b/components/policy/resources/PRESUBMIT.py
index 3870875aa379667a0dc5c6d59e95347b8e3934b3..19ea0ec12606960f27f1f513864f564e8b6e41e1 100644
--- a/components/policy/resources/PRESUBMIT.py
+++ b/components/policy/resources/PRESUBMIT.py
@@ -16,14 +16,17 @@ def _GetPolicyTemplates(template_path):
   # is actually maintained as a python dictionary.
   with open(template_path) as f:
     template_data = eval(f.read(), {})
-  policies = ( policy
+  try:
+    policies = ( policy
+                 for policy in template_data['policy_definitions']
+                 if policy['type'] != 'group' )
+    groups = ( policy['policies']
                for policy in template_data['policy_definitions']
-               if policy['type'] != 'group' )
-  groups = ( policy['policies']
-             for policy in template_data['policy_definitions']
-             if policy['type'] == 'group' )
-  subpolicies = ( policy for group in groups for policy in group )
-  return list(itertools.chain(policies, subpolicies))
+               if policy['type'] == 'group' )
+    subpolicies = ( policy for group in groups for policy in group )
+    return list(itertools.chain(policies, subpolicies))
+  except:
+    return list()
 
 def _CheckPolicyTemplatesSyntax(input_api, output_api):
   local_path = input_api.PresubmitLocalPath()