Revert to ? presence checks.

tools/dom/scripts/htmldartgenerator.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 system to generate
 dart:html APIs from the IDL database."""
 
 import emitter
 from generator import AnalyzeOperation, ConstantOutputOrder, \
@@ skipping 216 matching lines @@
 
       if is_void:
         call_emitter = call_emitter.Emit('$(INDENT)$!CALL;\n$(INDENT)return;\n')
       else:
         call_emitter = call_emitter.Emit('$(INDENT)return $!CALL;\n')
 
       version[0] += 1
       generate_call(stmts_emitter, call_emitter,
           version[0], signature_index, argument_count)
 
-    def IsDartTypeNullable(type_signature):
-      return type_signature not in ['int', 'double', 'num', 'bool']
-
     def GenerateChecksAndCall(signature_index, argument_count):
       checks = []
       for i in range(0, argument_count):
         argument = signatures[signature_index][i]
         parameter_name = parameter_names[i]
         test_type = self._DartType(argument.type.id)
-        nullable = argument.type.nullable
 
         if test_type in ['dynamic', 'Object']:
           checks.append('?%s' % parameter_name)
         elif not can_omit_type_check(test_type, i):
-          nullable = True
           checks.append('(%s is %s || %s == null)' % (
               parameter_name, test_type, parameter_name))
-
-        if not nullable and not IsDartTypeNullable(test_type):
+        else:
           for signature in signatures:
             if (len(signature) <= i or signature[i].id not in
                 parameter_name.split('_OR_')):
 
-              checks.append('%s != null' % parameter_name)
+              checks.append('?%s' % parameter_name)
               break
 
       # There can be multiple presence checks.  We need them all since a later
       # optional argument could have been passed by name, leaving 'holes'.
       checks.extend(['!?%s' % name for name in parameter_names[argument_count:]])
 
       GenerateCall(signature_index, argument_count, checks)
 
     # TODO: Optimize the dispatch to avoid repeated checks.
     if len(signatures) > 1:
@@ skipping 324 matching lines @@
     if interface.parents:
       parent = interface.parents[0]
       if IsPureInterface(parent.type.id):
         walk(interface.parents)
       else:
         walk(interface.parents[1:])
     return result
 
   def _DartType(self, type_name):
     return self._type_registry.DartType(type_name)