Bug 1519958 - Improve stack size of grid templates and re-enable styl…

…e struct size assertions disabled in the previous patch. r=boris

This re-enables the assertion which was disabled on the previous patch by doing
a bit of boxing around.

Differential Revision: https://phabricator.services.mozilla.com/D36599

components/style/properties/shorthands/position.mako.rs

@@ -353,8 +353,11 @@
                 GenericGridTemplateComponent::None
             };
 
-            Ok((GenericGridTemplateComponent::TrackList(template_rows),
-                template_cols, GridTemplateAreas::Areas(TemplateAreasArc(Arc::new(template_areas)))))
+            Ok((
+                GenericGridTemplateComponent::TrackList(Box::new(template_rows)),
+                template_cols,
+                GridTemplateAreas::Areas(TemplateAreasArc(Arc::new(template_areas)))
+            ))
         } else {
             let mut template_rows = GridTemplateComponent::parse(context, input)?;
             if let GenericGridTemplateComponent::TrackList(ref mut list) = template_rows {

components/style/values/generics/grid.rs

@@ -710,12 +710,12 @@ pub enum GenericGridTemplateComponent<L, I> {
         #[compute(field_bound)]
         #[resolve(field_bound)]
         #[shmem(field_bound)]
-        GenericTrackList<L, I>,
+        Box<GenericTrackList<L, I>>,
     ),
     /// A `subgrid <line-name-list>?`
     /// TODO: Support animations for this after subgrid is addressed in [grid-2] spec.
     #[animation(error)]
-    Subgrid(LineNameList),
+    Subgrid(Box<LineNameList>),
 }
 
 pub use self::GenericGridTemplateComponent as GridTemplateComponent;

components/style/values/specified/grid.rs

@@ -321,10 +321,11 @@ impl GridTemplateComponent<LengthPercentage, Integer> {
     ) -> Result<Self, ParseError<'i>> {
         if allow_grid_template_subgrids() {
             if let Ok(t) = input.try(|i| LineNameList::parse(context, i)) {
-                return Ok(GridTemplateComponent::Subgrid(t));
+                return Ok(GridTemplateComponent::Subgrid(Box::new(t)));
             }
         }
 
-        TrackList::parse(context, input).map(GridTemplateComponent::TrackList)
+        let track_list = TrackList::parse(context, input)?;
+        Ok(GridTemplateComponent::TrackList(Box::new(track_list)))
     }
 }