Add 'storage_only' template to make_computed_style_base.py.

third_party/WebKit/Source/build/scripts/make_computed_style_base.py

 #!/usr/bin/env python
 # 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.
 
 import math
 import sys
 
 import json5_generator
 import template_expander
 import make_style_builder
 
 from name_utilities import camel_case, lower_first, upper_first_letter, enum_for_css_keyword
 
 
 # Temporary hard-coded list of fields that are not CSS properties.
 # Ideally these would be specified in a .json5 file.
 NONPROPERTY_FIELDS = [
     # Style can not be shared.
     {'name': 'unique', 'field': {'template': 'monotonic_flag'}},
     # Whether this style is affected by these pseudo-classes.
     {'name': 'affectedByFocus', 'field': {'template': 'monotonic_flag'}},
     {'name': 'affectedByHover', 'field': {'template': 'monotonic_flag'}},
     {'name': 'affectedByActive', 'field': {'template': 'monotonic_flag'}},
     {'name': 'affectedByDrag', 'field': {'template': 'monotonic_flag'}},
     # A non-inherited property references a variable or @apply is used
     {'name': 'hasVariableReferenceFromNonInheritedProperty', 'field': {'template': 'monotonic_flag'}},
     # Explicitly inherits a non-inherited property
     {'name': 'hasExplicitlyInheritedProperties', 'field': {'template': 'monotonic_flag'}},
+    {'name': 'emptyState', 'field': {'template': 'storage_only', 'size': 1}},

[sashab, 2017/03/13 07:57:11]

# These properties only have generated storage, and their methods are
handwritten in ComputedStyle.
# TODO(shend): Remove these fields and delete the 'storage_only' template.

[shend, 2017/03/14 22:20:06]

Done.

 ]
 
 
 class Field(object):
     """
     The generated ComputedStyle object is made up of a series of Fields.
     Each Field has a name, size, type, etc, and a bunch of attributes to
     determine which methods it will be used in.
 
     A Field also has enough information to use any storage type in C++, such as
@@ skipping 157 matching lines @@
         setter_method_name='set' + field_name_suffix_upper,
         initial_method_name='initial' + field_name_suffix_upper,
         resetter_method_name='reset' + field_name_suffix_upper,
     )
 
 
 def _create_nonproperty_field(property_):
     """
     Create a nonproperty field from its name and return the Field object.
     """
-    # TODO(shend): Make this work for nonflags
-    assert property_['field']['template'] in ('flag', 'monotonic_flag'), \
+    # TODO(shend): Make this work for other templates (need to compute size correctly)
+    assert property_['field']['template'] in ('flag', 'monotonic_flag', 'storage_only'), \
         "Nonproperties with arbitrary templates are not yet supported"
     member_name = 'm_' + property_['name']
     field_name_upper = upper_first_letter(property_['name'])
 
     return Field(
         'nonproperty',
         name=member_name,
         property_name=property_['name'],
         type_name='bool',
         template=property_['field']['template'],
-        size=1,
+        size=property_['field'].get('size', 1),

[sashab, 2017/03/13 07:57:11]

Can you document somewhere (like at the top of the json5 file where it's
defined) that if this is not specified, it defaults to 1? Otherwise I think it
should fail, "a size must be specified" kind of thing

[shend, 2017/03/14 22:20:06]

Done.

         default_value='false',
         getter_method_name=property_['name'],
         setter_method_name='set' + field_name_upper,
         initial_method_name='initial' + field_name_upper,
         resetter_method_name='reset' + field_name_upper,
     )
 
 
 def _create_fields(properties):
     """
@@ skipping 149 matching lines @@
                     'mapping': [('k' + camel_case(k), enum_for_css_keyword(k)) for k in property_['keywords']],
                 }
 
         return {
             'include_paths': self._include_paths,
             'mappings': mappings,
         }
 
 if __name__ == '__main__':
     json5_generator.Maker(ComputedStyleBaseWriter).main()