diff --git a/components/style/properties/longhand/inherited_text.mako.rs b/components/style/properties/longhand/inherited_text.mako.rs
index c71e158d597..5428caa8a30 100644
--- a/components/style/properties/longhand/inherited_text.mako.rs
+++ b/components/style/properties/longhand/inherited_text.mako.rs
@@ -15,6 +15,9 @@
     #[derive(Debug, Clone, PartialEq, Copy, HeapSizeOf)]
     pub enum SpecifiedValue {
         Normal,
+        % if product == "gecko":
+            MozBlockHeight,
+        % endif
         Number(CSSFloat),
         LengthOrPercentage(specified::LengthOrPercentage),
     }
@@ -23,6 +26,9 @@
         fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
             match *self {
                 SpecifiedValue::Normal => dest.write_str("normal"),
+                % if product == "gecko":
+                    SpecifiedValue::MozBlockHeight => dest.write_str("-moz-block-height"),
+                % endif
                 SpecifiedValue::LengthOrPercentage(value) => value.to_css(dest),
                 SpecifiedValue::Number(number) => write!(dest, "{}", number),
             }
@@ -42,6 +48,11 @@
                 Token::Ident(ref value) if value.eq_ignore_ascii_case("normal") => {
                     Ok(SpecifiedValue::Normal)
                 }
+                % if product == "gecko":
+                Token::Ident(ref value) if value.eq_ignore_ascii_case("-moz-block-height") => {
+                    Ok(SpecifiedValue::MozBlockHeight)
+                }
+                % endif
                 _ => Err(()),
             }
         })
@@ -53,6 +64,9 @@
         #[derive(PartialEq, Copy, Clone, HeapSizeOf, Debug)]
         pub enum T {
             Normal,
+            % if product == "gecko":
+                MozBlockHeight,
+            % endif
             Length(Au),
             Number(CSSFloat),
         }
@@ -61,6 +75,9 @@
         fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
             match *self {
                 computed_value::T::Normal => dest.write_str("normal"),
+                % if product == "gecko":
+                    computed_value::T::MozBlockHeight => dest.write_str("-moz-block-height"),
+                % endif
                 computed_value::T::Length(length) => length.to_css(dest),
                 computed_value::T::Number(number) => write!(dest, "{}", number),
             }
@@ -76,6 +93,9 @@
         fn to_computed_value<Cx: TContext>(&self, context: &Cx) -> computed_value::T {
             match *self {
                 SpecifiedValue::Normal => computed_value::T::Normal,
+                % if product == "gecko":
+                    SpecifiedValue::MozBlockHeight => computed_value::T::MozBlockHeight,
+                % endif
                 SpecifiedValue::Number(value) => computed_value::T::Number(value),
                 SpecifiedValue::LengthOrPercentage(value) => {
                     match value {
diff --git a/ports/geckolib/properties.mako.rs b/ports/geckolib/properties.mako.rs
index 8a8a25c1b70..234f667a175 100644
--- a/ports/geckolib/properties.mako.rs
+++ b/ports/geckolib/properties.mako.rs
@@ -719,12 +719,29 @@ fn static_assert() {
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="InheritedText"
-                  skip_longhands="text-align">
+                  skip_longhands="text-align line-height">
 
     <% text_align_keyword = Keyword("text-align", "start end left right center justify -moz-center -moz-left " +
                                                   "-moz-right match-parent") %>
     <%call expr="impl_keyword('text_align', 'mTextAlign', text_align_keyword, need_clone=False)"></%call>
 
+    fn set_line_height(&mut self, v: longhands::line_height::computed_value::T) {
+        use style::properties::longhands::line_height::computed_value::T;
+        // FIXME: Align binary representations and ditch |match| for cast + static_asserts
+        match v {
+            T::Normal => self.gecko.mLineHeight.set_normal(),
+            T::Length(val) => self.gecko.mLineHeight.set_coord(val),
+            T::Number(val) => self.gecko.mLineHeight.set_factor(val),
+            T::MozBlockHeight =>
+                self.gecko.mLineHeight.set_enum(structs::NS_STYLE_LINE_HEIGHT_BLOCK_HEIGHT as i32),
+        }
+    }
+    fn copy_line_height_from(&mut self, other: &Self) {
+        debug_assert_unit_is_safe_to_copy(self.gecko.mLineHeight.mUnit);
+        self.gecko.mLineHeight.mUnit = other.gecko.mLineHeight.mUnit;
+        self.gecko.mLineHeight.mValue = other.gecko.mLineHeight.mValue;
+    }
+
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="Text"
diff --git a/ports/geckolib/values.rs b/ports/geckolib/values.rs
index c2d227970ee..6909989311d 100644
--- a/ports/geckolib/values.rs
+++ b/ports/geckolib/values.rs
@@ -11,10 +11,12 @@ use style::values::computed::{LengthOrPercentage, LengthOrPercentageOrAuto, Leng
 pub trait StyleCoordHelpers {
     fn set<T: ToGeckoStyleCoord>(&mut self, val: T);
     fn set_auto(&mut self);
+    fn set_normal(&mut self);
     fn set_coord(&mut self, val: Au);
     fn set_int(&mut self, val: i32);
     fn set_enum(&mut self, val: i32);
     fn set_percent(&mut self, val: f32);
+    fn set_factor(&mut self, val: f32);
 }
 
 impl StyleCoordHelpers for nsStyleCoord {
@@ -27,6 +29,11 @@ impl StyleCoordHelpers for nsStyleCoord {
         unsafe { *self.mValue.mInt.as_mut() = 0; }
     }
 
+    fn set_normal(&mut self) {
+        self.mUnit = nsStyleUnit::eStyleUnit_Normal;
+        unsafe { *self.mValue.mInt.as_mut() = 0; }
+    }
+
     fn set_coord(&mut self, val: Au) {
         self.mUnit = nsStyleUnit::eStyleUnit_Coord;
         unsafe { *self.mValue.mInt.as_mut() = val.0; }
@@ -46,6 +53,11 @@ impl StyleCoordHelpers for nsStyleCoord {
         self.mUnit = nsStyleUnit::eStyleUnit_Enumerated;
         unsafe { *self.mValue.mInt.as_mut() = val; }
     }
+
+    fn set_factor(&mut self, val: f32) {
+        self.mUnit = nsStyleUnit::eStyleUnit_Factor;
+        unsafe { *self.mValue.mFloat.as_mut() = val; }
+    }
 }
 
 pub trait ToGeckoStyleCoord {