Bug 1374233 - Part 8: Implement ToAnimatedValue for BorderCornerRadius.

BorderCornerRadius should always be non-negative, so we can implemennt
ToAnimatedValue for it directly, for properties:
1. border-{*}-radius
2. -moz-outline-{*}-radius

MozReview-Commit-ID: HEbeHz9Hfkd

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

@@ -62,7 +62,7 @@ ${helpers.gecko_keyword_conversion(Keyword('border-style',
                               spec="https://drafts.csswg.org/css-backgrounds/#border-%s-radius" % corner,
                               boxed=True,
                               flags="APPLIES_TO_FIRST_LETTER",
-                              animation_value_type="ComputedValue")}
+                              animation_value_type="BorderCornerRadius")}
 % endfor
 
 /// -moz-border-*-colors: color, string, enum, none, inherit/initial

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

@@ -76,7 +76,7 @@ ${helpers.predefined_type("outline-width",
         "computed::LengthOrPercentage::zero().into()",
         products="gecko",
         boxed=True,
-        animation_value_type="ComputedValue",
+        animation_value_type="BorderCornerRadius",
         spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-outline-radius)")}
 % endfor
 

components/style/values/animated/mod.rs

@@ -11,6 +11,7 @@
 use app_units::Au;
 use std::cmp::max;
 use values::computed::Angle as ComputedAngle;
+use values::computed::BorderCornerRadius as ComputedBorderCornerRadius;
 use values::computed::GreaterThanOrEqualToOneNumber as ComputedGreaterThanOrEqualToOneNumber;
 use values::computed::NonNegativeAu;
 use values::computed::NonNegativeLengthOrPercentage as ComputedNonNegativeLengthOrPercentage;
@@ -160,14 +161,22 @@ impl ToAnimatedValue for ComputedNonNegativeLengthOrPercentage {
 
     #[inline]
     fn from_animated_value(animated: Self::AnimatedValue) -> Self {
-        use values::computed::{LengthOrPercentage, Percentage};
-        match animated.0 {
-            LengthOrPercentage::Length(au) => LengthOrPercentage::Length(max(au, Au(0))).into(),
-            LengthOrPercentage::Percentage(percentage) => {
-                LengthOrPercentage::Percentage(Percentage(percentage.0.max(0.))).into()
-            },
-            _ => animated
-        }
+        animated.0.clamp_to_non_negative().into()
+    }
+}
+
+impl ToAnimatedValue for ComputedBorderCornerRadius {
+    type AnimatedValue = Self;
+
+    #[inline]
+    fn to_animated_value(self) -> Self {
+        self
+    }
+
+    #[inline]
+    fn from_animated_value(animated: Self::AnimatedValue) -> Self {
+        ComputedBorderCornerRadius::new(animated.0.width.clamp_to_non_negative(),
+                                        animated.0.height.clamp_to_non_negative())
     }
 }
 

components/style/values/computed/length.rs

@@ -351,6 +351,20 @@ impl LengthOrPercentage {
             },
         }
     }
+
+    /// Returns the clamped non-negative values.
+    #[inline]
+    pub fn clamp_to_non_negative(self) -> Self {
+        match self {
+            LengthOrPercentage::Length(length) => {
+                LengthOrPercentage::Length(Au(::std::cmp::max(length.0, 0)))
+            },
+            LengthOrPercentage::Percentage(percentage) => {
+                LengthOrPercentage::Percentage(Percentage(percentage.0.max(0.)))
+            },
+            _ => self
+        }
+    }
 }
 
 impl fmt::Debug for LengthOrPercentage {