Replace PositiveIntegerOrAuto by ColumnCount

It was its only use.

components/style/values/specified/column.rs

@@ -0,0 +1,26 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+//! Specified types for the column properties.
+
+use cssparser::Parser;
+use parser::{Parse, ParserContext};
+use style_traits::ParseError;
+use values::generics::column::ColumnCount as GenericColumnCount;
+use values::specified::PositiveInteger;
+
+/// A specified type for `column-count` values.
+pub type ColumnCount = GenericColumnCount<PositiveInteger>;
+
+impl Parse for ColumnCount {
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        if input.try(|i| i.expect_ident_matching("auto")).is_ok() {
+            return Ok(GenericColumnCount::Auto);
+        }
+        Ok(GenericColumnCount::Integer(PositiveInteger::parse(context, input)?))
+    }
+}