style: Simplify -x-span property.

Differential Revision: https://phabricator.services.mozilla.com/D42914

components/style/values/specified/table.rs

@@ -1,34 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
-
-//! Specified types for table properties.
-
-use crate::parser::{Parse, ParserContext};
-use cssparser::Parser;
-use style_traits::{ParseError, StyleParseErrorKind};
-
-#[derive(
-    Clone,
-    Copy,
-    Debug,
-    MallocSizeOf,
-    PartialEq,
-    SpecifiedValueInfo,
-    ToComputedValue,
-    ToCss,
-    ToResolvedValue,
-    ToShmem,
-)]
-/// span. for `<col span>` pres attr
-pub struct XSpan(#[css(skip)] pub i32);
-
-impl Parse for XSpan {
-    // never parse it, only set via presentation attribute
-    fn parse<'i, 't>(
-        _: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<XSpan, ParseError<'i>> {
-        Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
-    }
-}