diff --git a/components/style/properties/data.py b/components/style/properties/data.py
index 44190948ccf..d8244ef8622 100644
--- a/components/style/properties/data.py
+++ b/components/style/properties/data.py
@@ -153,7 +153,7 @@ def arg_to_bool(arg):
 class Longhand(object):
     def __init__(self, style_struct, name, spec=None, animation_value_type=None, derived_from=None, keyword=None,
                  predefined_type=None, custom_cascade=False, experimental=False, internal=False,
-                 need_clone=False, need_index=False, gecko_ffi_name=None, depend_on_viewport_size=False,
+                 need_clone=False, need_index=False, gecko_ffi_name=None,
                  allowed_in_keyframe_block=True, cast_type='u8',
                  has_uncacheable_values=False, logical=False, alias=None, extra_prefixes=None, boxed=False,
                  flags=None, allowed_in_page_rule=False, allow_quirks=False, ignored_when_colors_disabled=False,
@@ -173,7 +173,6 @@ class Longhand(object):
         self.need_index = need_index
         self.has_uncacheable_values = has_uncacheable_values
         self.gecko_ffi_name = gecko_ffi_name or "m" + self.camel_case
-        self.depend_on_viewport_size = depend_on_viewport_size
         self.derived_from = (derived_from or "").split()
         self.cast_type = cast_type
         self.logical = arg_to_bool(logical)