diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 5311f79f71f..f6f28924721 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -1349,27 +1349,7 @@ fn static_assert() {
     }
     % endfor
 
-    pub fn set_grid_auto_flow(&mut self, v: longhands::grid_auto_flow::computed_value::T) {
-        use gecko_bindings::structs::NS_STYLE_GRID_AUTO_FLOW_ROW;
-        use gecko_bindings::structs::NS_STYLE_GRID_AUTO_FLOW_COLUMN;
-        use gecko_bindings::structs::NS_STYLE_GRID_AUTO_FLOW_DENSE;
-        use properties::longhands::grid_auto_flow::computed_value::AutoFlow::{Row, Column};
-
-        self.gecko.mGridAutoFlow = 0;
-
-        let value = match v.autoflow {
-            Row => NS_STYLE_GRID_AUTO_FLOW_ROW,
-            Column => NS_STYLE_GRID_AUTO_FLOW_COLUMN,
-        };
-
-        self.gecko.mGridAutoFlow |= value as u8;
-
-        if v.dense {
-            self.gecko.mGridAutoFlow |= NS_STYLE_GRID_AUTO_FLOW_DENSE as u8;
-        }
-    }
-
-    ${impl_simple_copy('grid_auto_flow', 'mGridAutoFlow')}
+    ${impl_simple_type_with_conversion("grid_auto_flow")}
 
     pub fn set_grid_template_areas(&mut self, v: longhands::grid_template_areas::computed_value::T) {
         use gecko_bindings::bindings::Gecko_NewGridTemplateAreasValue;
@@ -1791,21 +1771,7 @@ fn static_assert() {
         unsafe { transmute(self.gecko.mFont.weight) }
     }
 
-    pub fn set_font_synthesis(&mut self, v: longhands::font_synthesis::computed_value::T) {
-        use gecko_bindings::structs::{NS_FONT_SYNTHESIS_WEIGHT, NS_FONT_SYNTHESIS_STYLE};
-
-        self.gecko.mFont.synthesis = 0;
-        if v.weight {
-            self.gecko.mFont.synthesis |= NS_FONT_SYNTHESIS_WEIGHT as u8;
-        }
-        if v.style {
-            self.gecko.mFont.synthesis |= NS_FONT_SYNTHESIS_STYLE as u8;
-        }
-    }
-
-    pub fn copy_font_synthesis_from(&mut self, other: &Self) {
-        self.gecko.mFont.synthesis = other.gecko.mFont.synthesis;
-    }
+    ${impl_simple_type_with_conversion("font_synthesis", "mFont.synthesis")}
 
     pub fn set_font_size_adjust(&mut self, v: longhands::font_size_adjust::computed_value::T) {
         use properties::longhands::font_size_adjust::computed_value::T;
@@ -3703,25 +3669,7 @@ fn static_assert() {
         }
     }
 
-    pub fn set_text_emphasis_position(&mut self, v: longhands::text_emphasis_position::computed_value::T) {
-        use properties::longhands::text_emphasis_position::*;
-
-        let mut result = match v.0 {
-            HorizontalWritingModeValue::Over => structs::NS_STYLE_TEXT_EMPHASIS_POSITION_OVER as u8,
-            HorizontalWritingModeValue::Under => structs::NS_STYLE_TEXT_EMPHASIS_POSITION_UNDER as u8,
-        };
-        match v.1 {
-            VerticalWritingModeValue::Right => {
-                result |= structs::NS_STYLE_TEXT_EMPHASIS_POSITION_RIGHT as u8;
-            }
-            VerticalWritingModeValue::Left => {
-                result |= structs::NS_STYLE_TEXT_EMPHASIS_POSITION_LEFT as u8;
-            }
-        }
-        self.gecko.mTextEmphasisPosition = result;
-    }
-
-    <%call expr="impl_simple_copy('text_emphasis_position', 'mTextEmphasisPosition')"></%call>
+    ${impl_simple_type_with_conversion("text_emphasis_position")}
 
     pub fn set_text_emphasis_style(&mut self, v: longhands::text_emphasis_style::computed_value::T) {
         use properties::longhands::text_emphasis_style::computed_value::T;
diff --git a/components/style/properties/longhand/font.mako.rs b/components/style/properties/longhand/font.mako.rs
index 3ba7576fe37..cf2d9b8d7ec 100644
--- a/components/style/properties/longhand/font.mako.rs
+++ b/components/style/properties/longhand/font.mako.rs
@@ -1161,7 +1161,7 @@ ${helpers.single_keyword_system("font-variant-caps",
     }
 </%helpers:longhand>
 
-<%helpers:longhand products="gecko" name="font-synthesis" animation_value_type="none"
+<%helpers:longhand products="gecko" name="font-synthesis" animation_value_type="discrete"
                    spec="https://drafts.csswg.org/css-fonts/#propdef-font-synthesis">
     use std::fmt;
     use style_traits::ToCss;
@@ -1221,6 +1221,34 @@ ${helpers.single_keyword_system("font-variant-caps",
             _ => Err(())
         }
     }
+
+    #[cfg(feature = "gecko")]
+    impl From<u8> for SpecifiedValue {
+        fn from(bits: u8) -> SpecifiedValue {
+            use gecko_bindings::structs;
+
+            SpecifiedValue {
+                weight: bits & structs::NS_FONT_SYNTHESIS_WEIGHT as u8 != 0,
+                style: bits & structs::NS_FONT_SYNTHESIS_STYLE as u8 != 0
+            }
+        }
+    }
+
+    #[cfg(feature = "gecko")]
+    impl From<SpecifiedValue> for u8 {
+        fn from(v: SpecifiedValue) -> u8 {
+            use gecko_bindings::structs;
+
+            let mut bits: u8 = 0;
+            if v.weight {
+                bits |= structs::NS_FONT_SYNTHESIS_WEIGHT as u8;
+            }
+            if v.style {
+                bits |= structs::NS_FONT_SYNTHESIS_STYLE as u8;
+            }
+            bits
+        }
+    }
 </%helpers:longhand>
 
 ${helpers.single_keyword_system("font-stretch",
diff --git a/components/style/properties/longhand/inherited_text.mako.rs b/components/style/properties/longhand/inherited_text.mako.rs
index f78059017b5..8a4aea6a2b0 100644
--- a/components/style/properties/longhand/inherited_text.mako.rs
+++ b/components/style/properties/longhand/inherited_text.mako.rs
@@ -624,7 +624,7 @@ ${helpers.predefined_type("word-spacing",
     }
 </%helpers:longhand>
 
-<%helpers:longhand name="text-emphasis-position" animation_value_type="none" products="gecko"
+<%helpers:longhand name="text-emphasis-position" animation_value_type="discrete" products="gecko"
                    spec="https://drafts.csswg.org/css-text-decor/#propdef-text-emphasis-position">
     use values::computed::ComputedValueAsSpecified;
     use style_traits::ToCss;
@@ -682,6 +682,32 @@ ${helpers.predefined_type("word-spacing",
                 SpecifiedValue(horiz, vert)
             }
         }
+
+        impl From<u8> for SpecifiedValue {
+            fn from(bits: u8) -> SpecifiedValue {
+                SpecifiedValue::from_gecko_keyword(bits as u32)
+            }
+        }
+
+        impl From<SpecifiedValue> for u8 {
+            fn from(v: SpecifiedValue) -> u8 {
+                use gecko_bindings::structs;
+
+                let mut result = match v.0 {
+                    HorizontalWritingModeValue::Over => structs::NS_STYLE_TEXT_EMPHASIS_POSITION_OVER,
+                    HorizontalWritingModeValue::Under => structs::NS_STYLE_TEXT_EMPHASIS_POSITION_UNDER,
+                };
+                match v.1 {
+                    VerticalWritingModeValue::Right => {
+                        result |= structs::NS_STYLE_TEXT_EMPHASIS_POSITION_RIGHT;
+                    }
+                    VerticalWritingModeValue::Left => {
+                        result |= structs::NS_STYLE_TEXT_EMPHASIS_POSITION_LEFT;
+                    }
+                };
+                result as u8
+            }
+        }
     % endif
 </%helpers:longhand>
 
diff --git a/components/style/properties/longhand/position.mako.rs b/components/style/properties/longhand/position.mako.rs
index ac220446e64..46cc63143f0 100644
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhand/position.mako.rs
@@ -292,7 +292,7 @@ ${helpers.predefined_type("object-position",
 <%helpers:longhand name="grid-auto-flow"
         spec="https://drafts.csswg.org/css-grid/#propdef-grid-auto-flow"
         products="gecko"
-        animation_value_type="none">
+        animation_value_type="discrete">
     use std::fmt;
     use style_traits::ToCss;
     use values::computed::ComputedValueAsSpecified;
@@ -372,6 +372,43 @@ ${helpers.predefined_type("object-position",
             Err(())
         }
     }
+
+    #[cfg(feature = "gecko")]
+    impl From<u8> for SpecifiedValue {
+        fn from(bits: u8) -> SpecifiedValue {
+            use gecko_bindings::structs;
+            use self::computed_value::AutoFlow;
+
+            SpecifiedValue {
+                autoflow:
+                    if bits & structs::NS_STYLE_GRID_AUTO_FLOW_ROW as u8 != 0 {
+                        AutoFlow::Row
+                    } else {
+                        AutoFlow::Column
+                    },
+                dense:
+                    bits & structs::NS_STYLE_GRID_AUTO_FLOW_DENSE as u8 != 0,
+            }
+        }
+    }
+
+    #[cfg(feature = "gecko")]
+    impl From<SpecifiedValue> for u8 {
+        fn from(v: SpecifiedValue) -> u8 {
+            use gecko_bindings::structs;
+            use self::computed_value::AutoFlow;
+
+            let mut result: u8 = match v.autoflow {
+                AutoFlow::Row => structs::NS_STYLE_GRID_AUTO_FLOW_ROW as u8,
+                AutoFlow::Column => structs::NS_STYLE_GRID_AUTO_FLOW_COLUMN as u8,
+            };
+
+            if v.dense {
+                result |= structs::NS_STYLE_GRID_AUTO_FLOW_DENSE as u8;
+            }
+            result
+        }
+    }
 </%helpers:longhand>
 
 <%helpers:longhand name="grid-template-areas"