stylo: Preserve the variant of scale() values in computed transforms

components/style/properties/gecko.mako.rs

@@ -3073,6 +3073,9 @@ fn static_assert() {
                 ${transform_function_arm("TranslateY", "translatey", ["lop"])}
                 ${transform_function_arm("TranslateZ", "translatez", ["length"])}
                 ${transform_function_arm("Translate", "translate3d", ["lop", "lop", "length"])}
+                ${transform_function_arm("ScaleX", "scalex", ["number"])}
+                ${transform_function_arm("ScaleY", "scaley", ["number"])}
+                ${transform_function_arm("ScaleZ", "scalez", ["number"])}
                 ${transform_function_arm("Scale", "scale3d", ["number"] * 3)}
                 ${transform_function_arm("Rotate", "rotate3d", ["number"] * 3 + ["angle"])}
                 ${transform_function_arm("Perspective", "perspective", ["length"])}
@@ -3197,6 +3200,9 @@ fn static_assert() {
                 ${computed_operation_arm("TranslateY", "translatey", ["lop"])}
                 ${computed_operation_arm("TranslateZ", "translatez", ["length"])}
                 ${computed_operation_arm("Translate", "translate3d", ["lop", "lop", "length"])}
+                ${computed_operation_arm("ScaleX", "scalex", ["number"])}
+                ${computed_operation_arm("ScaleY", "scaley", ["number"])}
+                ${computed_operation_arm("ScaleZ", "scalez", ["number"])}
                 ${computed_operation_arm("Scale", "scale3d", ["number"] * 3)}
                 ${computed_operation_arm("Rotate", "rotate3d", ["number"] * 3 + ["angle"])}
                 ${computed_operation_arm("Perspective", "perspective", ["length"])}

components/style/properties/helpers/animated_properties.mako.rs

@@ -1160,6 +1160,9 @@ impl ToAnimatedZero for TransformOperation {
             TransformOperation::Scale(..) => {
                 Ok(TransformOperation::Scale(1.0, 1.0, 1.0))
             },
+            TransformOperation::ScaleX(_) => Ok(TransformOperation::ScaleX(1.)),
+            TransformOperation::ScaleY(_) => Ok(TransformOperation::ScaleY(1.)),
+            TransformOperation::ScaleZ(_) => Ok(TransformOperation::ScaleZ(1.)),
             TransformOperation::Rotate(x, y, z, a) => {
                 let (x, y, z, _) = TransformList::get_normalized_vector_and_angle(x, y, z, a);
                 Ok(TransformOperation::Rotate(x, y, z, Angle::zero()))

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

@@ -689,6 +689,9 @@ ${helpers.predefined_type(
             Translate(computed::LengthOrPercentage,
                       computed::LengthOrPercentage,
                       computed::Length),
+            ScaleX(CSSFloat),
+            ScaleY(CSSFloat),
+            ScaleZ(CSSFloat),
             Scale(CSSFloat, CSSFloat, CSSFloat),
             Rotate(CSSFloat, CSSFloat, CSSFloat, computed::Angle),
             Perspective(computed::Length),
@@ -1292,15 +1295,15 @@ ${helpers.predefined_type(
                     }
                     SpecifiedOperation::ScaleX(sx) => {
                         let sx = sx.to_computed_value(context);
-                        result.push(computed_value::ComputedOperation::Scale(sx, 1.0, 1.0));
+                        result.push(computed_value::ComputedOperation::ScaleX(sx));
                     }
                     SpecifiedOperation::ScaleY(sy) => {
                         let sy = sy.to_computed_value(context);
-                        result.push(computed_value::ComputedOperation::Scale(1.0, sy, 1.0));
+                        result.push(computed_value::ComputedOperation::ScaleY(sy));
                     }
                     SpecifiedOperation::ScaleZ(sz) => {
                         let sz = sz.to_computed_value(context);
-                        result.push(computed_value::ComputedOperation::Scale(1.0, 1.0, sz));
+                        result.push(computed_value::ComputedOperation::ScaleZ(sz));
                     }
                     SpecifiedOperation::Scale3D(sx, sy, sz) => {
                         let sx = sx.to_computed_value(context);
@@ -1435,6 +1438,18 @@ ${helpers.predefined_type(
                                               ToComputedValue::from_computed_value(ty),
                                               ToComputedValue::from_computed_value(tz)));
                         }
+                        computed_value::ComputedOperation::ScaleX(ref sx) => {
+                            result.push(SpecifiedOperation::ScaleX(
+                                              ToComputedValue::from_computed_value(sx)));
+                        }
+                        computed_value::ComputedOperation::ScaleY(ref sy) => {
+                            result.push(SpecifiedOperation::ScaleY(
+                                              ToComputedValue::from_computed_value(sy)));
+                        }
+                        computed_value::ComputedOperation::ScaleZ(ref sz) => {
+                            result.push(SpecifiedOperation::ScaleZ(
+                                              ToComputedValue::from_computed_value(sz)));
+                        }
                         computed_value::ComputedOperation::Scale(ref sx, ref sy, ref sz) => {
                             result.push(SpecifiedOperation::Scale3D(
                                     Number::from_computed_value(sx),

components/style/values/computed/transform.rs

@@ -89,6 +89,15 @@ impl TransformList {
                 ComputedOperation::Perspective(d) => {
                     Self::create_perspective_matrix(d.px())
                 }
+                ComputedOperation::ScaleX(sx) => {
+                    Transform3D::create_scale(sx, 1., 1.)
+                }
+                ComputedOperation::ScaleY(sy) => {
+                    Transform3D::create_scale(1., sy, 1.)
+                }
+                ComputedOperation::ScaleZ(sz) => {
+                    Transform3D::create_scale(1., 1., sz)
+                }
                 ComputedOperation::Scale(sx, sy, sz) => {
                     Transform3D::create_scale(sx, sy, sz)
                 }