style: Make appearance: button behave like auto on various elements.

Differential Revision: https://phabricator.services.mozilla.com/D83434

components/style/properties/data.py

@@ -334,6 +334,7 @@ class Longhand(object):
                 "BackgroundRepeat",
                 "BorderImageRepeat",
                 "BorderStyle",
+                "ButtonAppearance",
                 "Clear",
                 "ColumnCount",
                 "Contain",

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

@@ -639,6 +639,25 @@ ${helpers.predefined_type(
     gecko_ffi_name="mDefaultAppearance",
 )}
 
+// A UA-sheet only property that controls the effect of `appearance: button`
+// on the element: `-moz-button-appearance: allow` means the element is rendered
+// with button appearance, and `-moz-button-appearance: disallow` is treated
+// like `appearance: auto`.
+//
+// https://github.com/w3c/csswg-drafts/issues/5174 proposes to simplify `button`
+// to mean `auto` unconditionally, at which point this property can be removed.
+${helpers.predefined_type(
+    "-moz-button-appearance",
+    "ButtonAppearance",
+    "computed::ButtonAppearance::Allow",
+    engines="gecko",
+    animation_value_type="none",
+    needs_context=False,
+    spec="Internal (not web-exposed)",
+    enabled_in="ua",
+    gecko_ffi_name="mButtonAppearance",
+)}
+
 ${helpers.single_keyword(
     "-moz-orient",
     "inline block horizontal vertical",

components/style/values/computed/box.rs

@@ -12,8 +12,8 @@ use crate::values::generics::box_::VerticalAlign as GenericVerticalAlign;
 use crate::values::specified::box_ as specified;
 
 pub use crate::values::specified::box_::{AnimationName, Appearance, BreakBetween, BreakWithin};
-pub use crate::values::specified::box_::{Clear as SpecifiedClear, Float as SpecifiedFloat};
+pub use crate::values::specified::box_::{ButtonAppearance, Clear as SpecifiedClear};
-pub use crate::values::specified::box_::{Contain, Display, Overflow};
+pub use crate::values::specified::box_::{Float as SpecifiedFloat, Contain, Display, Overflow};
 pub use crate::values::specified::box_::{OverflowAnchor, OverflowClipBox, OverscrollBehavior};
 pub use crate::values::specified::box_::{
     ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStrictness, ScrollSnapType,

components/style/values/computed/mod.rs

@@ -43,7 +43,7 @@ pub use self::border::{BorderCornerRadius, BorderRadius, BorderSpacing};
 pub use self::border::{BorderImageRepeat, BorderImageSideWidth};
 pub use self::border::{BorderImageSlice, BorderImageWidth};
 pub use self::box_::{AnimationIterationCount, AnimationName, Contain};
-pub use self::box_::{Appearance, BreakBetween, BreakWithin, Clear, Float};
+pub use self::box_::{Appearance, BreakBetween, BreakWithin, ButtonAppearance, Clear, Float};
 pub use self::box_::{Display, Overflow, OverflowAnchor, TransitionProperty};
 pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize};
 pub use self::box_::{ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStrictness, ScrollSnapType};

components/style/values/specified/box.rs

@@ -1842,6 +1842,31 @@ pub enum Appearance {
     Count,
 }
 
+/// The effect of `appearance: button` on an element.
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    Eq,
+    Hash,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToCss,
+    ToComputedValue,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(u8)]
+pub enum ButtonAppearance {
+    /// `appearance: button` means the element is rendered with button
+    /// appearance.
+    Allow,
+    /// `appearance: button` is treated like `appearance: auto`.
+    Disallow,
+}
+
 /// A kind of break between two boxes.
 ///
 /// https://drafts.csswg.org/css-break/#break-between

components/style/values/specified/mod.rs

@@ -37,7 +37,7 @@ pub use self::border::{BorderCornerRadius, BorderImageSlice, BorderImageWidth};
 pub use self::border::{BorderImageRepeat, BorderImageSideWidth};
 pub use self::border::{BorderRadius, BorderSideWidth, BorderSpacing, BorderStyle};
 pub use self::box_::{AnimationIterationCount, AnimationName, Contain, Display};
-pub use self::box_::{Appearance, BreakBetween, BreakWithin};
+pub use self::box_::{Appearance, BreakBetween, BreakWithin, ButtonAppearance};
 pub use self::box_::{Clear, Float, Overflow, OverflowAnchor};
 pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize};
 pub use self::box_::{ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStrictness, ScrollSnapType};