style: Parse scroll-snap-stop style and propagate it to APZ side

Depends on D146147

Differential Revision: https://phabricator.services.mozilla.com/D145850

components/style/properties/counted_unknown_properties.py

@@ -73,7 +73,6 @@ COUNTED_UNKNOWN_PROPERTIES = [
     "-webkit-perspective-origin-y",
     "-webkit-margin-before-collapse",
     "-webkit-border-before-style",
-    "scroll-snap-stop",
     "-webkit-margin-bottom-collapse",
     "-webkit-ruby-position",
     "-webkit-column-break-after",

components/style/properties/data.py

@@ -492,6 +492,7 @@ class Longhand(Property):
                 "ScrollbarGutter",
                 "ScrollSnapAlign",
                 "ScrollSnapAxis",
+                "ScrollSnapStop",
                 "ScrollSnapStrictness",
                 "ScrollSnapType",
                 "TextAlign",

components/style/properties/longhands/box.mako.rs

@@ -285,6 +285,15 @@ ${helpers.predefined_type(
     animation_value_type="discrete",
 )}
 
+${helpers.predefined_type(
+    "scroll-snap-stop",
+    "ScrollSnapStop",
+    "computed::ScrollSnapStop::Normal",
+    engines="gecko",
+    spec="https://drafts.csswg.org/css-scroll-snap-1/#scroll-snap-stop",
+    animation_value_type="discrete",
+)}
+
 % for (axis, logical) in ALL_AXES:
     ${helpers.predefined_type(
         "overscroll-behavior-" + axis,

components/style/values/computed/box.rs

@@ -15,8 +15,9 @@ pub use crate::values::specified::box_::{
     AnimationName, AnimationTimeline, Appearance, BreakBetween, BreakWithin,
     Clear as SpecifiedClear, Contain, ContainerName, ContainerType, ContentVisibility, Display,
     Float as SpecifiedFloat, Overflow, OverflowAnchor, OverflowClipBox,
-    OverscrollBehavior, ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStrictness,
+    OverscrollBehavior, ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop,
-    ScrollSnapType, ScrollbarGutter, TouchAction, TransitionProperty, WillChange,
+    ScrollSnapStrictness, ScrollSnapType, ScrollbarGutter, TouchAction,
+    TransitionProperty, WillChange,
 };
 
 /// A computed value for the `vertical-align` property.

components/style/values/computed/mod.rs

@@ -49,7 +49,8 @@ pub use self::box_::{AnimationIterationCount, AnimationName, AnimationTimeline,
 pub use self::box_::{Appearance, BreakBetween, BreakWithin, Clear, ContentVisibility, Float};
 pub use self::box_::{Display, Overflow, OverflowAnchor, TransitionProperty};
 pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize, ScrollbarGutter};
-pub use self::box_::{ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStrictness, ScrollSnapType};
+pub use self::box_::{ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop};
+pub use self::box_::{ScrollSnapStrictness, ScrollSnapType};
 pub use self::box_::{TouchAction, VerticalAlign, WillChange};
 pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust};
 pub use self::column::ColumnCount;

components/style/values/specified/box.rs

@@ -1080,6 +1080,28 @@ impl ToCss for ScrollSnapAlign {
     }
 }
 
+#[allow(missing_docs)]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    Eq,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToComputedValue,
+    ToCss,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(u8)]
+pub enum ScrollSnapStop {
+    Normal,
+    Always,
+}
+
 #[allow(missing_docs)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 #[derive(

components/style/values/specified/mod.rs

@@ -40,7 +40,8 @@ pub use self::box_::{AnimationIterationCount, AnimationName, AnimationTimeline,
 pub use self::box_::{Appearance, BreakBetween, BreakWithin, ContainerName, ContainerType};
 pub use self::box_::{Clear, ContentVisibility, Float, Overflow, OverflowAnchor};
 pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize, ScrollbarGutter};
-pub use self::box_::{ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStrictness, ScrollSnapType};
+pub use self::box_::{ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop};
+pub use self::box_::{ScrollSnapStrictness, ScrollSnapType};
 pub use self::box_::{TouchAction, TransitionProperty, VerticalAlign, WillChange};
 pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust};
 pub use self::column::ColumnCount;