style: Rename -moz-math-script-level to math-depth.

This renames the internal -moz-math-script-level property in order to
prepare for full math-depth support. Currently, the property is guarded
under a disabled-by-default flag, so there should be no observable
behavior change.

Differential Revision: https://phabricator.services.mozilla.com/D91285

components/style/properties/cascade.rs

@@ -963,7 +963,7 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
     fn handle_mathml_scriptlevel_if_needed(&mut self) {
         use crate::values::generics::NonNegative;
 
-        if !self.seen.contains(LonghandId::MozScriptLevel) &&
+        if !self.seen.contains(LonghandId::MathDepth) &&
            !self.seen.contains(LonghandId::MozScriptMinSize) &&
            !self.seen.contains(LonghandId::MozScriptSizeMultiplier) {
             return;
@@ -980,7 +980,7 @@ impl<'a, 'b: 'a> Cascade<'a, 'b> {
             let parent_font = builder.get_parent_font().gecko();
 
             let delta =
-                font.mScriptLevel.saturating_sub(parent_font.mScriptLevel);
+                font.mMathDepth.saturating_sub(parent_font.mMathDepth);
 
             if delta == 0 {
                 return;

components/style/properties/data.py

@@ -360,7 +360,7 @@ class Longhand(object):
                 "MasonryAutoFlow",
                 "MozForceBrokenImageIcon",
                 "MozListReversed",
-                "MozScriptLevel",
+                "MathDepth",
                 "MozScriptMinSize",
                 "MozScriptSizeMultiplier",
                 "TextDecorationSkipInk",

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

@@ -228,14 +228,15 @@ ${helpers.predefined_type(
 )}
 
 ${helpers.predefined_type(
-    "-moz-script-level",
-    "MozScriptLevel",
+    "math-depth",
+    "MathDepth",
     "0",
     engines="gecko",
+    gecko_pref="layout.css.math-depth.enabled",
+    has_effect_on_gecko_scrollbars=False,
     animation_value_type="none",
     enabled_in="ua",
-    gecko_ffi_name="mScriptLevel",
-    spec="Internal (not web-exposed)",
+    spec="https://mathml-refresh.github.io/mathml-core/#the-math-script-level-property",
 )}
 
 ${helpers.single_keyword(

components/style/properties/properties.mako.rs

@@ -1342,8 +1342,8 @@ impl LonghandId {
             // preferences properly, see bug 1165538.
             LonghandId::MozMinFontSizeRatio |
 
-            // Needed to do font-size for MathML. :(
-            LonghandId::MozScriptLevel |
+            // font-size depends on math-depth's computed value.
+            LonghandId::MathDepth |
             % endif
 
             // Needed to compute the first available font, in order to

components/style/values/computed/font.rs

@@ -811,20 +811,20 @@ impl ToComputedValue for specified::MozScriptMinSize {
     }
 }
 
-/// The computed value of the -moz-script-level property.
-pub type MozScriptLevel = i8;
+/// The computed value of the math-depth property.
+pub type MathDepth = i8;
 
 #[cfg(feature = "gecko")]
-impl ToComputedValue for specified::MozScriptLevel {
-    type ComputedValue = MozScriptLevel;
+impl ToComputedValue for specified::MathDepth {
+    type ComputedValue = MathDepth;
 
     fn to_computed_value(&self, cx: &Context) -> i8 {
         use crate::properties::longhands::math_style::SpecifiedValue as MathStyleValue;
         use std::{cmp, i8};
 
         let int = match *self {
-            specified::MozScriptLevel::Auto => {
-                let parent = cx.builder.get_parent_font().clone__moz_script_level() as i32;
+            specified::MathDepth::Auto => {
+                let parent = cx.builder.get_parent_font().clone_math_depth() as i32;
                 let style = cx.builder.get_parent_font().clone_math_style();
                 if style == MathStyleValue::Compact {
                     parent + 1
@@ -832,17 +832,17 @@ impl ToComputedValue for specified::MozScriptLevel {
                     parent
                 }
             },
-            specified::MozScriptLevel::Relative(rel) => {
-                let parent = cx.builder.get_parent_font().clone__moz_script_level();
+            specified::MathDepth::Relative(rel) => {
+                let parent = cx.builder.get_parent_font().clone_math_depth();
                 parent as i32 + rel
             },
-            specified::MozScriptLevel::MozAbsolute(abs) => abs,
+            specified::MathDepth::MozAbsolute(abs) => abs,
         };
         cmp::min(int, i8::MAX as i32) as i8
     }
 
     fn from_computed_value(other: &i8) -> Self {
-        specified::MozScriptLevel::MozAbsolute(*other as i32)
+        specified::MathDepth::MozAbsolute(*other as i32)
     }
 }
 

components/style/values/computed/mod.rs

@@ -59,7 +59,7 @@ pub use self::font::{FontFeatureSettings, FontVariantLigatures, FontVariantNumer
 pub use self::font::{FontSize, FontSizeAdjust, FontStretch, FontSynthesis};
 pub use self::font::{FontVariantAlternates, FontWeight};
 pub use self::font::{FontVariantEastAsian, FontVariationSettings};
-pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XLang, XTextZoom};
+pub use self::font::{MathDepth, MozScriptMinSize, MozScriptSizeMultiplier, XLang, XTextZoom};
 pub use self::image::{Gradient, Image, LineDirection, MozImageRect};
 pub use self::length::{CSSPixelLength, ExtremumLength, NonNegativeLength};
 pub use self::length::{Length, LengthOrNumber, LengthPercentage, NonNegativeLengthOrNumber};

components/style/values/specified/font.rs

@@ -2311,7 +2311,7 @@ impl Parse for MozScriptMinSize {
 ///
 /// The main effect of scriptlevel is to control the font size.
 /// https://www.w3.org/TR/MathML3/chapter3.html#presm.scriptlevel
-pub enum MozScriptLevel {
+pub enum MathDepth {
     /// Change `font-size` relatively.
     Relative(i32),
     /// Change `font-size` absolutely.
@@ -2325,17 +2325,17 @@ pub enum MozScriptLevel {
     Auto,
 }
 
-impl Parse for MozScriptLevel {
+impl Parse for MathDepth {
     fn parse<'i, 't>(
         _: &ParserContext,
         input: &mut Parser<'i, 't>,
-    ) -> Result<MozScriptLevel, ParseError<'i>> {
+    ) -> Result<MathDepth, ParseError<'i>> {
         // We don't bother to handle calc here.
         if let Ok(i) = input.try_parse(|i| i.expect_integer()) {
-            return Ok(MozScriptLevel::Relative(i));
+            return Ok(MathDepth::Relative(i));
         }
         input.expect_ident_matching("auto")?;
-        Ok(MozScriptLevel::Auto)
+        Ok(MathDepth::Auto)
     }
 }
 

components/style/values/specified/mod.rs

@@ -53,7 +53,7 @@ pub use self::font::{FontFeatureSettings, FontVariantLigatures, FontVariantNumer
 pub use self::font::{FontSize, FontSizeAdjust, FontSizeKeyword, FontStretch, FontSynthesis};
 pub use self::font::{FontVariantAlternates, FontWeight};
 pub use self::font::{FontVariantEastAsian, FontVariationSettings};
-pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XLang, XTextZoom};
+pub use self::font::{MathDepth, MozScriptMinSize, MozScriptSizeMultiplier, XLang, XTextZoom};
 pub use self::image::{EndingShape as GradientEndingShape, Gradient};
 pub use self::image::{Image, MozImageRect};
 pub use self::length::{AbsoluteLength, CalcLengthPercentage, CharacterWidth};