IDL: Add Function and VoidFunction as built-in callback function types

Source/bindings/scripts/idl_types.py

 # Copyright 2014 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.
 """IDL type handling.
 
 Classes:
 IdlTypeBase
  IdlType
  IdlUnionType
  IdlArrayOrSequenceType
@@ skipping 66 matching lines @@
 }
 
 STRING_TYPES = frozenset([
     # http://heycam.github.io/webidl/#es-interface-call (step 10.11)
     # (Interface object [[Call]] method's string types.)
     'String',
     'ByteString',
     'USVString',
 ])
 
+STANDARD_CALLBACK_FUNCTIONS = frozenset([
+    # http://heycam.github.io/webidl/#common-Function
+    'Function',
+    # http://heycam.github.io/webidl/#common-VoidFunction
+    'VoidFunction',
+])
+
 
 ################################################################################
 # Inheritance
 ################################################################################
 
 ancestors = defaultdict(list)  # interface_name -> ancestors
 
 def inherits_interface(interface_name, ancestor_name):
     return (interface_name == ancestor_name or
             ancestor_name in ancestors[interface_name])
@@ skipping 22 matching lines @@
 
 
 ################################################################################
 # IdlType
 ################################################################################
 
 class IdlType(IdlTypeBase):
     # FIXME: incorporate Nullable, etc.
     # to support types like short?[] vs. short[]?, instead of treating these
     # as orthogonal properties (via flags).
-    callback_functions = set()
+    callback_functions = set(STANDARD_CALLBACK_FUNCTIONS)
     callback_interfaces = set()
     dictionaries = set()
     enums = {}  # name -> values
 
     def __init__(self, base_type, is_unrestricted=False):
         super(IdlType, self).__init__()
         if is_unrestricted:
             self.base_type = 'unrestricted %s' % base_type
         else:
             self.base_type = base_type
@@ skipping 255 matching lines @@
     def is_nullable(self):
         return True
 
     @property
     def name(self):
         return self.inner_type.name + 'OrNull'
 
     def resolve_typedefs(self, typedefs):
         self.inner_type = self.inner_type.resolve_typedefs(typedefs)
         return self