style: Add forced-color-adjust property

Adds the forced-color-adjust property and ForcedColorAdjust keywords.
Updates tweak_when_ignoring_colors to check for `none` value of that property when determining if a color adjustment in needed.
Adds a check for `none` when styling selections to make sure they can be styled in forced color modes.

Differential Revision: https://phabricator.services.mozilla.com/D169000

components/style/properties/cascade.rs

@@ -424,6 +424,12 @@ fn tweak_when_ignoring_colors(
         return;
     }
 
+    // Always honor colors if forced-color-adjust is set to none.
+    let forced = context.builder.get_inherited_text().clone_forced_color_adjust();
+    if forced == computed::ForcedColorAdjust::None {
+        return;
+    }
+
     // Don't override background-color on ::-moz-color-swatch. It is set as an
     // author style (via the style attribute), but it's pretty important for it
     // to show up for obvious reasons :)

components/style/properties/data.py

@@ -480,6 +480,7 @@ class Longhand(Property):
                 "PageOrientation",
                 "Percentage",
                 "PrintColorAdjust",
+                "ForcedColorAdjust",
                 "Resize",
                 "RubyPosition",
                 "SVGOpacity",

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

@@ -388,3 +388,14 @@ ${helpers.predefined_type(
     animation_value_type="discrete",
     spec="https://www.w3.org/TR/css-text-4/#hyphenate-character",
 )}
+
+${helpers.predefined_type(
+    "forced-color-adjust",
+    "ForcedColorAdjust",
+    "computed::ForcedColorAdjust::Auto",
+    engines="gecko",
+    gecko_pref="layout.css.forced-color-adjust.enabled",
+    has_effect_on_gecko_scrollbars=False,
+    animation_value_type="discrete",
+    spec="https://drafts.csswg.org/css-color-adjust-1/#forced-color-adjust-prop",
+)}

components/style/properties/properties.mako.rs

@@ -935,6 +935,7 @@ CASCADE_GROUPS = {
         "font-family",
         # color-scheme affects how system colors resolve.
         "color-scheme",
+        "forced-color-adjust",
     ],
 }
 def in_late_group(p):

components/style/values/computed/color.rs

@@ -12,7 +12,7 @@ use cssparser::{Color as CSSParserColor, RGBA};
 use std::fmt;
 use style_traits::{CssWriter, ToCss};
 
-pub use crate::values::specified::color::{ColorScheme, PrintColorAdjust};
+pub use crate::values::specified::color::{ColorScheme, PrintColorAdjust, ForcedColorAdjust};
 
 /// The computed value of the `color` property.
 pub type ColorPropertyValue = RGBA;

components/style/values/computed/mod.rs

@@ -59,7 +59,7 @@ pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize, S
 pub use self::box_::{ScrollAxis, ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop};
 pub use self::box_::{ScrollSnapStrictness, ScrollSnapType, ScrollTimelineName};
 pub use self::box_::{TouchAction, VerticalAlign, WillChange};
-pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust};
+pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust, ForcedColorAdjust};
 pub use self::column::ColumnCount;
 pub use self::counters::{Content, ContentItem, CounterIncrement, CounterReset, CounterSet};
 pub use self::easing::TimingFunction;

components/style/values/specified/color.rs

@@ -1073,3 +1073,25 @@ pub enum PrintColorAdjust {
     /// Respect specified colors.
     Exact,
 }
+
+/// https://drafts.csswg.org/css-color-adjust-1/#forced-color-adjust-prop
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToCss,
+    ToComputedValue,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(u8)]
+pub enum ForcedColorAdjust {
+    /// Adjust colors if needed.
+    Auto,
+    /// Respect specified colors.
+    None,
+}

components/style/values/specified/mod.rs

@@ -45,7 +45,7 @@ pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize, S
 pub use self::box_::{ScrollAxis, ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop};
 pub use self::box_::{ScrollSnapStrictness, ScrollSnapType, ScrollTimelineName};
 pub use self::box_::{TouchAction, TransitionProperty, VerticalAlign, WillChange};
-pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust};
+pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust, ForcedColorAdjust};
 pub use self::column::ColumnCount;
 pub use self::counters::{Content, ContentItem, CounterIncrement, CounterReset, CounterSet};
 pub use self::easing::TimingFunction;