IDL: Avoid generating empty ConstantConfiguration arrays

Source/bindings/scripts/v8_interface.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 # coding=utf-8
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 209 matching lines @@
         'any_type_attributes': any_type_attributes,
         'constructors': constructors,
         'has_custom_constructor': bool(custom_constructors),
         'has_event_constructor': has_event_constructor,
         'interface_length':
             interface_length(interface, constructors + custom_constructors),
         'is_constructor_raises_exception': extended_attributes.get('RaisesException') == 'Constructor',  # [RaisesException=Constructor]
         'named_constructor': named_constructor,
     })
 
+    constants = [constant_context(constant) for constant in interface.constants]
+
     # Constants
     context.update({
-        'constants': [constant_context(constant)
-                      for constant in interface.constants],
+        'constants': constants,
         'do_not_check_constants': 'DoNotCheckConstants' in extended_attributes,
+        'has_constant_configuration': any(
+            not constant['runtime_enabled_function']
+            for constant in constants),
     })
 
     # Attributes
     attributes = [v8_attributes.attribute_context(interface, attribute)
                   for attribute in interface.attributes]
     context.update({
         'attributes': attributes,
         'has_accessors': any(attribute['is_expose_js_accessors'] and attribute['should_be_exposed_to_script'] for attribute in attributes),
         'has_attribute_configuration': any(
              not (attribute['is_expose_js_accessors'] or
@@ skipping 871 matching lines @@
         deleter = next(
             method
             for method in interface.operations
             if ('deleter' in method.specials and
                 len(method.arguments) == 1 and
                 str(method.arguments[0].idl_type) == 'DOMString'))
     except StopIteration:
         return None
 
     return property_deleter(deleter)