Use original WebKit IDL database for dart:html generation.

lib/dom/scripts/systemfrog.py

 #!/usr/bin/python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """This module provides shared functionality for the systems to generate
 frog binding from the IDL database."""
 
 import os
 from generator import *
@@ skipping 144 matching lines @@
     factory_provider = '_' + interface_name + 'FactoryProvider'
     emitter = self._system._ImplFileEmitter(factory_provider)
     emitter.Emit(
         template,
         FACTORYPROVIDER=factory_provider,
         CONSTRUCTOR=interface_name,
         PARAMETERS=constructor_info.ParametersImplementationDeclaration(),
         NAMEDCONSTRUCTOR=constructor_info.name or interface_name,
         ARGUMENTS=constructor_info.ParametersAsArgumentList())
 
-  def _NarrowToImplementationType(self, type_name):
+  def _ShouldNarrowToImplementationType(self, type_name):
     # TODO(sra): Move into the 'system' and cache the result.
     if type_name == 'EventListener':
       # Callbacks are typedef functions so don't have a class.
-      return type_name
+      return False
     if self._system._database.HasInterface(type_name):
       interface = self._system._database.GetInterface(type_name)
       if RecognizeCallback(interface):
         # Callbacks are typedef functions so don't have a class.
-        return type_name
+        return False
       elif type_name == 'MediaQueryListListener':
         # Somewhat like a callback.  See Issue 3338.
-        return type_name
+        return False
       else:
-        return self._ImplClassName(type_name)
+        return True
+    return False
+
+  def _NarrowToImplementationType(self, type_name):
+    if self._ShouldNarrowToImplementationType(type_name):
+      return self._ImplClassName(type_name)
     return type_name
 
   def _NarrowInputType(self, type_name):
     return self._NarrowToImplementationType(DartType(type_name))
 
   def _NarrowOutputType(self, type_name):
     return self._NarrowToImplementationType(DartType(type_name))
 
   def AddConstant(self, constant):
     # Since we are currently generating native classes without interfaces,
@@ skipping 200 matching lines @@
     if native_body:
       native_string = " '''" + native_body + "'''"
 
     self._members_emitter.Emit(
         '\n'
         '  $TYPE $NAME($PARAMS) native$NATIVESTRING;\n',
         TYPE=self._NarrowOutputType(info.type_name),
         NAME=info.name,
         PARAMS=params,
         NATIVESTRING=native_string)