Implement serialization for transform functions.

Preserve more information from transform function parsing.
Preserve angle unit while parsing.
Simplify SpecifiedMatrix.
Use the write! macro for formatting with a helper called Css.
Implement ToCss for &T if T implements ToCss.
Add some tests and update others.

closes #15194

tests/unit/style/parsing/box_.rs

@@ -26,3 +26,11 @@ fn test_will_change() {
     assert!(parse(will_change::parse, "contents, inherit, initial").is_err());
     assert!(parse(will_change::parse, "transform scroll-position").is_err());
 }
+
+#[test]
+fn test_transform_translate() {
+    use style::properties::longhands::transform;
+    assert_roundtrip_with_context!(transform::parse, "translate(2px)");
+    assert_roundtrip_with_context!(transform::parse, "translate(2px, 5px)");
+    assert!(parse(transform::parse, "translate(2px foo)").is_err());
+}

tests/unit/style/parsing/image.rs

@@ -28,8 +28,7 @@ fn test_linear_gradient() {
     assert_roundtrip_with_context!(Image::parse, "linear-gradient(to right top, red, green)");
 
     // Parsing with <angle>
-    assert_roundtrip_with_context!(Image::parse, "linear-gradient(45deg, red, green)",
-                                                 "linear-gradient(0.7853982rad, red, green)");
+    assert_roundtrip_with_context!(Image::parse, "linear-gradient(45deg, red, green)");
 
     // Parsing with more than two entries in <color-stop-list>
     assert_roundtrip_with_context!(Image::parse, "linear-gradient(red, yellow, green)");

tests/unit/style/parsing/inherited_box.rs

@@ -9,7 +9,6 @@ use style::stylesheets::Origin;
 
 #[test]
 fn image_orientation_longhand_should_parse_properly() {
-    use std::f32::consts::PI;
     use style::properties::longhands::image_orientation;
     use style::properties::longhands::image_orientation::SpecifiedValue;
     use style::values::specified::Angle;
@@ -21,11 +20,11 @@ fn image_orientation_longhand_should_parse_properly() {
     assert_eq!(flip, SpecifiedValue { angle: None, flipped: true });
 
     let zero = parse_longhand!(image_orientation, "0deg");
-    assert_eq!(zero, SpecifiedValue { angle: Some(Angle::from_radians(0.0)), flipped: false });
+    assert_eq!(zero, SpecifiedValue { angle: Some(Angle::from_degrees(0.0)), flipped: false });
 
     let negative_rad = parse_longhand!(image_orientation, "-1rad");
     assert_eq!(negative_rad, SpecifiedValue { angle: Some(Angle::from_radians(-1.0)), flipped: false });
 
     let flip_with_180 = parse_longhand!(image_orientation, "180deg flip");
-    assert_eq!(flip_with_180, SpecifiedValue { angle: Some(Angle::from_radians(PI)), flipped: true });
+    assert_eq!(flip_with_180, SpecifiedValue { angle: Some(Angle::from_degrees(180.0)), flipped: true });
 }

tests/unit/style/properties/serialization.rs

@@ -962,6 +962,8 @@ mod shorthand_serialization {
 
     mod transform {
         pub use super::*;
+        use style::properties::longhands::transform::SpecifiedOperation;
+        use style::values::specified::{Angle, Number};
 
         #[test]
         fn should_serialize_none_correctly() {
@@ -982,6 +984,46 @@ mod shorthand_serialization {
             assert_eq!(try_serialize.is_ok(), true);
             assert_eq!(s, "none");
         }
+
+        #[inline(always)]
+        fn validate_serialization<T: ToCss>(op: &T, expected_string: &'static str) {
+            let css_string = op.to_css_string();
+            assert_eq!(css_string, expected_string);
+        }
+
+        #[test]
+        fn transform_scale() {
+            validate_serialization(&SpecifiedOperation::Scale(Number::new(1.3), None), "scale(1.3)");
+            validate_serialization(
+                &SpecifiedOperation::Scale(Number::new(2.0), Some(Number::new(2.0))),
+                "scale(2, 2)");
+            validate_serialization(&SpecifiedOperation::ScaleX(Number::new(42.0)), "scaleX(42)");
+            validate_serialization(&SpecifiedOperation::ScaleY(Number::new(0.3)), "scaleY(0.3)");
+            validate_serialization(&SpecifiedOperation::ScaleZ(Number::new(1.0)), "scaleZ(1)");
+            validate_serialization(
+                &SpecifiedOperation::Scale3D(Number::new(4.0), Number::new(5.0), Number::new(6.0)),
+                "scale3d(4, 5, 6)");
+        }
+
+        #[test]
+        fn transform_skew() {
+            validate_serialization(
+                &SpecifiedOperation::Skew(Angle::from_degrees(42.3), None),
+                "skew(42.3deg)");
+            validate_serialization(
+                &SpecifiedOperation::Skew(Angle::from_gradians(-50.0), Some(Angle::from_turns(0.73))),
+                "skew(-50grad, 0.73turn)");
+            validate_serialization(
+                &SpecifiedOperation::SkewX(Angle::from_radians(0.31)), "skewX(0.31rad)");
+        }
+
+        #[test]
+        fn transform_rotate() {
+            validate_serialization(
+                &SpecifiedOperation::Rotate(Angle::from_turns(35.0)),
+                "rotate(35turn)"
+            )
+        }
     }
 
     mod quotes {

tests/wpt/metadata-css/css-transforms-1_dev/html/css-transform-style-evaluation-validation.htm.ini

@@ -1,26 +0,0 @@
-[css-transform-style-evaluation-validation.htm]
-  type: testharness
-  [transform: Check rotate(0) input.]
-    expected: FAIL
-
-  [transform: Check rotateX(0) input.]
-    expected: FAIL
-
-  [transform: Check rotateY(0) input.]
-    expected: FAIL
-
-  [transform: Check rotateZ(0) input.]
-    expected: FAIL
-
-  [transform: Check rotate(string) input.]
-    expected: FAIL
-
-  [transform: Check rotateX(string) input.]
-    expected: FAIL
-
-  [transform: Check rotateY(string) input.]
-    expected: FAIL
-
-  [transform: Check rotateZ(string) input.]
-    expected: FAIL
-