Bindings generation emits (more) correct null checking

Source/bindings/dart/scripts/dart_interface.py

Index: Source/bindings/dart/scripts/dart_interface.py
diff --git a/Source/bindings/dart/scripts/dart_interface.py b/Source/bindings/dart/scripts/dart_interface.py
index 3690874396741d286e12f34f4f345691c3dba4c2..c647e4cb13beec3666caf7b33e7ff5070e45de12 100644
--- a/Source/bindings/dart/scripts/dart_interface.py
+++ b/Source/bindings/dart/scripts/dart_interface.py
@@ -837,7 +837,7 @@ def generate_constructor(interface, constructor):
     return {
         'argument_list': constructor_argument_list(interface, constructor),
         # TODO(terry): Use dart_methods.generate_argument instead constructor_argument.
-        'arguments': [constructor_argument(argument, index)
+        'arguments': [constructor_argument(interface, argument, index)
                       for index, argument in enumerate(constructor.arguments)],
         'has_exception_state':
             # [RaisesException=Constructor]
@@ -885,7 +885,7 @@ def constructor_argument_list(interface, constructor):
 
 # TODO(terry): Eliminate this function use dart_methods.generate_argument instead
 #              for all constructor arguments.
-def constructor_argument(argument, index):
+def constructor_argument(interface, argument, index):
     idl_type = argument.idl_type
     default_value = str(argument.default_value) if argument.default_value else None
 
@@ -905,7 +905,7 @@ def constructor_argument(argument, index):
         'is_optional': argument.is_optional,
         'is_strict_type_checking': False,  # Required for overload resolution
         'name': argument.name,
-        'dart_value_to_local_cpp_value': dart_methods.dart_value_to_local_cpp_value(argument, index),
+        'dart_value_to_local_cpp_value': dart_methods.dart_value_to_local_cpp_value(interface, argument, index),
     }
     return argument_content
 
@@ -1006,9 +1006,10 @@ def property_getter(getter, cpp_arguments):
                                                                 release=idl_type.release)}
 
 
-def property_setter(setter):
+def property_setter(interface, setter):
     idl_type = setter.arguments[1].idl_type
     extended_attributes = setter.extended_attributes
+    interface_extended_attributes = interface.extended_attributes
     is_raises_exception = 'RaisesException' in extended_attributes
     return {
         'has_strict_type_checking':
@@ -1021,7 +1022,7 @@ def property_setter(setter):
         'is_raises_exception': is_raises_exception,
         'name': DartUtilities.cpp_name(setter),
         'dart_value_to_local_cpp_value': idl_type.dart_value_to_local_cpp_value(
-            extended_attributes, 'propertyValue', False),
+            interface_extended_attributes, extended_attributes, 'propertyValue', False),
     }
 
 
@@ -1075,7 +1076,7 @@ def indexed_property_setter(interface):
     except StopIteration:
         return None
 
-    return property_setter(setter)
+    return property_setter(interface, setter)
 
 
 def indexed_property_deleter(interface):
@@ -1129,7 +1130,7 @@ def named_property_setter(interface):
     except StopIteration:
         return None
 
-    return property_setter(setter)
+    return property_setter(interface, setter)
 
 
 def named_property_deleter(interface):