IDL: initialize union member variables (to null/zero)

Source/bindings/scripts/v8_types.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 185 matching lines @@
     return base_idl_type + '*'
 
 
 def cpp_type_initializer(idl_type):
     """Returns a string containing a C++ initialization statement for the
     corresponding type.
 
     |idl_type| argument is of type IdlType.
     """
 
-    if (idl_type.is_numeric_type):
+    base_idl_type = idl_type.base_type
+
+    if idl_type.native_array_element_type:
+        return ''
+    if idl_type.is_numeric_type:
         return ' = 0'
-    if idl_type.base_type == 'boolean':
+    if base_idl_type == 'boolean':
         return ' = false'
-    return ''
+    if (base_idl_type in NON_WRAPPER_TYPES or
+        base_idl_type in CPP_SPECIAL_CONVERSION_RULES or
+        base_idl_type == 'any' or
+        idl_type.is_string_type or
+        idl_type.is_enum):
+        return ''
+    return ' = nullptr'
 
 
 def cpp_type_union(idl_type, extended_attributes=None, raw_type=False):
     # FIXME: Need to revisit the design of union support.
     # http://crbug.com/240176
     return None
 
 
 def cpp_type_initializer_union(idl_type):
     return (member_type.cpp_type_initializer for member_type in idl_type.member_types)
@@ skipping 585 matching lines @@
 
 
 def is_explicit_nullable(idl_type):
     # Nullable type that isn't implicit nullable (see above.) For such types,
     # we use Nullable<T> or similar explicit ways to represent a null value.
     return idl_type.is_nullable and not idl_type.is_implicit_nullable
 
 IdlTypeBase.is_implicit_nullable = property(is_implicit_nullable)
 IdlUnionType.is_implicit_nullable = False
 IdlTypeBase.is_explicit_nullable = property(is_explicit_nullable)