--- a/servo/components/style/properties/gecko.mako.rs
+++ b/servo/components/style/properties/gecko.mako.rs
@@ -2166,49 +2166,47 @@ fn static_assert() {
                         .expect("Expected length or percentage for vertical-align");
                     T::LengthOrPercentage(v)
                 }
         }
     }
 
     <%call expr="impl_coord_copy('vertical_align', 'mVerticalAlign')"></%call>
 
+    % for kind in ["before", "after"]:
     // Temp fix for Bugzilla bug 24000.
     // Map 'auto' and 'avoid' to false, and 'always', 'left', and 'right' to true.
     // "A conforming user agent may interpret the values 'left' and 'right'
     // as 'always'." - CSS2.1, section 13.3.1
-    pub fn set_page_break_before(&mut self, v: longhands::page_break_before::computed_value::T) {
-        use computed_values::page_break_before::T;
+    pub fn set_page_break_${kind}(&mut self, v: longhands::page_break_${kind}::computed_value::T) {
+        use computed_values::page_break_${kind}::T;
+
         let result = match v {
             T::auto   => false,
             T::always => true,
             T::avoid  => false,
             T::left   => true,
             T::right  => true
         };
-        self.gecko.mBreakBefore = result;
-    }
-
-    ${impl_simple_copy('page_break_before', 'mBreakBefore')}
+        self.gecko.mBreak${kind.title()} = result;
+    }
+
+    ${impl_simple_copy('page_break_' + kind, 'mBreak' + kind.title())}
 
     // Temp fix for Bugzilla bug 24000.
-    // See set_page_break_before for detail.
-    pub fn set_page_break_after(&mut self, v: longhands::page_break_after::computed_value::T) {
-        use computed_values::page_break_after::T;
-        let result = match v {
-            T::auto   => false,
-            T::always => true,
-            T::avoid  => false,
-            T::left   => true,
-            T::right  => true
-        };
-        self.gecko.mBreakAfter = result;
-    }
-
-    ${impl_simple_copy('page_break_after', 'mBreakAfter')}
+    // See set_page_break_before/after for detail.
+    pub fn clone_page_break_${kind}(&self) -> longhands::page_break_${kind}::computed_value::T {
+        use computed_values::page_break_${kind}::T;
+
+        match self.gecko.mBreak${kind.title()} {
+            true => T::always,
+            false => T::auto,
+        }
+    }
+    % endfor
 
     pub fn set_scroll_snap_points_x(&mut self, v: longhands::scroll_snap_points_x::computed_value::T) {
         match v.0 {
             None => self.gecko.mScrollSnapPointsX.set_value(CoordDataValue::None),
             Some(l) => l.to_gecko_style_coord(&mut self.gecko.mScrollSnapPointsX),
         };
     }
 

--- a/servo/components/style/properties/longhand/box.mako.rs
+++ b/servo/components/style/properties/longhand/box.mako.rs
@@ -196,17 +196,18 @@
     }
 </%helpers:single_keyword_computed>
 
 <%helpers:single_keyword_computed name="clear"
                                   values="none left right both"
                                   // https://drafts.csswg.org/css-logical-props/#float-clear
                                   extra_specified="inline-start inline-end"
                                   needs_conversion="True"
-                                  animation_value_type="none"
+                                  gecko_inexhaustive="True"
+                                  animation_value_type="discrete"
                                   gecko_enum_prefix="StyleClear"
                                   gecko_ffi_name="mBreakType"
                                   spec="https://www.w3.org/TR/CSS2/visuren.html#flow-control">
     no_viewport_percentage!(SpecifiedValue);
     impl ToComputedValue for SpecifiedValue {
         type ComputedValue = computed_value::T;
 
         #[inline]
@@ -2029,22 +2030,22 @@
                          flags="CREATES_STACKING_CONTEXT",
                          animation_value_type="discrete")}
 
 // TODO add support for logical values recto and verso
 ${helpers.single_keyword("page-break-after",
                          "auto always avoid left right",
                          products="gecko",
                          spec="https://drafts.csswg.org/css2/page.html#propdef-page-break-after",
-                         animation_value_type="none")}
+                         animation_value_type="discrete")}
 ${helpers.single_keyword("page-break-before",
                          "auto always avoid left right",
                          products="gecko",
                          spec="https://drafts.csswg.org/css2/page.html#propdef-page-break-before",
-                         animation_value_type="none")}
+                         animation_value_type="discrete")}
 ${helpers.single_keyword("page-break-inside",
                          "auto avoid",
                          products="gecko",
                          gecko_ffi_name="mBreakInside",
                          gecko_constant_prefix="NS_STYLE_PAGE_BREAK",
                          spec="https://drafts.csswg.org/css2/page.html#propdef-page-break-inside",
                          animation_value_type="discrete")}
 
@@ -2082,17 +2083,18 @@
                          extra_prefixes="moz webkit",
                          animation_value_type="discrete")}
 
 ${helpers.single_keyword("transform-box",
                          "border-box fill-box view-box",
                          gecko_enum_prefix="StyleGeometryBox",
                          products="gecko",
                          spec="https://drafts.csswg.org/css-transforms/#transform-box",
-                         animation_value_type="none")}
+                         gecko_inexhaustive="True",
+                         animation_value_type="discrete")}
 
 // `auto` keyword is not supported in gecko yet.
 ${helpers.single_keyword("transform-style",
                          "auto flat preserve-3d" if product == "servo" else
                          "flat preserve-3d",
                          spec="https://drafts.csswg.org/css-transforms/#transform-style-property",
                          extra_prefixes="moz webkit",
                          flags="CREATES_STACKING_CONTEXT FIXPOS_CB",
@@ -2352,17 +2354,18 @@
                           disable_when_testing="True")}
 
 ${helpers.single_keyword("-moz-orient",
                           "inline block horizontal vertical",
                           products="gecko",
                           gecko_ffi_name="mOrient",
                           gecko_enum_prefix="StyleOrient",
                           spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-orient)",
-                          animation_value_type="none")}
+                          gecko_inexhaustive="True",
+                          animation_value_type="discrete")}
 
 <%helpers:longhand name="will-change" products="gecko" animation_value_type="none"
                    spec="https://drafts.csswg.org/css-will-change/#will-change">
     use cssparser::serialize_identifier;
     use std::fmt;
     use style_traits::ToCss;
     use values::computed::ComputedValueAsSpecified;