Rename animatable to interpolable in CSSProperties.in

Source/build/scripts/css_properties.py

 #!/usr/bin/env python
 # Copyright 2014 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 in_generator
 from name_utilities import lower_first
 
 
 class CSSProperties(in_generator.Writer):
     defaults = {
         'alias_for': None,
         'runtime_flag': None,
         'longhands': '',
-        'animatable': False,
+        'interpolable': False,
         'inherited': False,
         'font': False,
         'svg': False,
         'name_for_methods': None,
         'use_handlers_for': None,
         'getter': None,
         'setter': None,
         'initial': None,
         'type_name': None,
         'converter': None,
         'custom_all': False,
         'custom_initial': False,
         'custom_inherit': False,
         'custom_value': False,
         'builder_skip': False,
         'direction_aware': False,
     }
 
     valid_values = {
-        'animatable': (True, False),
+        'interpolable': (True, False),
         'inherited': (True, False),
         'font': (True, False),
         'svg': (True, False),
         'custom_all': (True, False),
         'custom_initial': (True, False),
         'custom_inherit': (True, False),
         'custom_value': (True, False),
         'builder_skip': (True, False),
         'direction_aware': (True, False),
     }
@@ skipping 38 matching lines @@
     """
     return ''.join(word.capitalize() for word in css_name.split('-'))
 
 
 def css_name_to_enum(css_name):
     return 'CSSProperty' + camelcase_css_name(css_name)
 
 
 def css_alias_name_to_enum(css_name):
     return 'CSSPropertyAlias' + camelcase_css_name(css_name)