Auto merge of #15662 - canaltinova:column, r=Manishearth

Fix parsing methods of column-{gap,width}

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They weren't accepting {normal, auto} keywords. Fixed parsing methods of these properties.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #15088 (github issue number if applicable).

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- [X] There are tests for these changes

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components/style/properties/gecko.mako.rs

@@ -628,6 +628,7 @@ impl Debug for ${style_struct.gecko_struct_name} {
     # Types used with predefined_type()-defined properties that we can auto-generate.
     predefined_types = {
         "length::LengthOrAuto": impl_style_coord,
+        "length::LengthOrNormal": impl_style_coord,
         "Length": impl_absolute_length,
         "Position": impl_position,
         "LengthOrPercentage": impl_style_coord,
@@ -3041,7 +3042,7 @@ clip-path
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="Column"
-                  skip_longhands="column-count column-gap column-rule-width">
+                  skip_longhands="column-count column-rule-width">
 
     #[allow(unused_unsafe)]
     pub fn set_column_count(&mut self, v: longhands::column_count::computed_value::T) {
@@ -3057,17 +3058,6 @@ clip-path
 
     ${impl_simple_copy('column_count', 'mColumnCount')}
 
-    pub fn set_column_gap(&mut self, v: longhands::column_gap::computed_value::T) {
-        use values::Either;
-
-        match v {
-            Either::First(len) => self.gecko.mColumnGap.set(len),
-            Either::Second(_normal) => self.gecko.mColumnGap.set_value(CoordDataValue::Normal),
-        }
-    }
-
-    <%call expr="impl_coord_copy('column_gap', 'mColumnGap')"></%call>
-
     <% impl_app_units("column_rule_width", "mColumnRuleWidth", need_clone=True,
                       round_to_pixels=True) %>
 </%self:impl_trait>