bindings: Throw a type error if converting an interface or callback function fails.

third_party/WebKit/Source/bindings/scripts/v8_callback_function.py

 # Copyright 2016 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.
 
 """Generate template values for a callback function.
 
 Design doc: http://www.chromium.org/developers/design-documents/idl-compiler
 """
 
 from v8_globals import includes  # pylint: disable=W0403
@@ skipping 21 matching lines @@
     includes.update(CALLBACK_FUNCTION_CPP_INCLUDES)
     idl_type = callback_function.idl_type
     idl_type_str = str(idl_type)
     forward_declarations = []
     for argument in callback_function.arguments:
         if argument.idl_type.is_interface_type:
             forward_declarations.append(argument.idl_type)
         argument.idl_type.add_includes_for_type(callback_function.extended_attributes)
 
     context = {
+        # While both |callback_function_name| and |cpp_class| are identical at
+        # the moment, the two are being defined because their values may change
+        # in the future (e.g. if we support [ImplementedAs=] in callback
+        # functions).
+        'callback_function_name': callback_function.name,
         'cpp_class': callback_function.name,
         'cpp_includes': sorted(includes),
         'forward_declarations': sorted(forward_declarations),
         'header_includes': sorted(CALLBACK_FUNCTION_H_INCLUDES),
         'idl_type': idl_type_str,
     }
 
     if idl_type_str != 'void':
         context.update({
             'return_cpp_type': idl_type.cpp_type + '&',
@@ skipping 22 matching lines @@
     ]
     argument_declarations.extend(
         '%s %s' % (argument.idl_type.callback_cpp_type, argument.name)
         for argument in arguments)
     if return_cpp_type:
         argument_declarations.append('%s returnValue' % return_cpp_type)
     return {
         'argument_declarations': argument_declarations,
         'arguments': [argument_context(argument) for argument in arguments],
     }