diff --git a/components/style/gecko_bindings/sugar/mod.rs b/components/style/gecko_bindings/sugar/mod.rs
index 159beb6a332..1d4208f5421 100644
--- a/components/style/gecko_bindings/sugar/mod.rs
+++ b/components/style/gecko_bindings/sugar/mod.rs
@@ -13,6 +13,7 @@ mod ns_style_auto_array;
 pub mod ns_style_coord;
 mod ns_t_array;
 mod ns_timing_function;
+mod origin_flags;
 pub mod ownership;
 pub mod refptr;
 mod style_complex_color;
diff --git a/components/style/gecko_bindings/sugar/origin_flags.rs b/components/style/gecko_bindings/sugar/origin_flags.rs
new file mode 100644
index 00000000000..1a121ee98ad
--- /dev/null
+++ b/components/style/gecko_bindings/sugar/origin_flags.rs
@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Helper to iterate over `OriginFlags` bits.
+
+use gecko_bindings::structs::OriginFlags;
+use gecko_bindings::structs::OriginFlags_Author;
+use gecko_bindings::structs::OriginFlags_User;
+use gecko_bindings::structs::OriginFlags_UserAgent;
+use stylesheets::Origin;
+
+impl OriginFlags {
+    /// Returns an iterator over the origins present in the `OriginFlags`,
+    /// in order from highest priority (author) to lower (user agent).
+    pub fn iter(self) -> OriginFlagsIter {
+        OriginFlagsIter {
+            origin_flags: self,
+            cur: 0,
+        }
+    }
+}
+
+/// Iterates over the origins present in an `OriginFlags`, in order from
+/// highest priority (author) to lower (user agent).
+pub struct OriginFlagsIter {
+    origin_flags: OriginFlags,
+    cur: usize,
+}
+
+impl Iterator for OriginFlagsIter {
+    type Item = Origin;
+
+    fn next(&mut self) -> Option<Origin> {
+        loop {
+            let (bit, origin) = match self.cur {
+                0 => (OriginFlags_Author, Origin::Author),
+                1 => (OriginFlags_User, Origin::User),
+                2 => (OriginFlags_UserAgent, Origin::UserAgent),
+                _ => return None,
+            };
+
+            self.cur += 1;
+
+            if (self.origin_flags & bit).0 != 0 {
+                return Some(origin);
+            }
+        }
+    }
+}
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index d20fce6fb13..f4a767024ac 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -74,6 +74,7 @@ use style::gecko_bindings::structs::{nsCSSFontFaceRule, nsCSSCounterStyleRule};
 use style::gecko_bindings::structs::{nsRestyleHint, nsChangeHint, PropertyValuePair};
 use style::gecko_bindings::structs::IterationCompositeOperation;
 use style::gecko_bindings::structs::MallocSizeOf;
+use style::gecko_bindings::structs::OriginFlags;
 use style::gecko_bindings::structs::RawGeckoGfxMatrix4x4;
 use style::gecko_bindings::structs::RawGeckoPresContextOwned;
 use style::gecko_bindings::structs::SeenPtrs;
@@ -954,11 +955,14 @@ pub extern "C" fn Servo_StyleSet_FlushStyleSheets(
 pub extern "C" fn Servo_StyleSet_NoteStyleSheetsChanged(
     raw_data: RawServoStyleSetBorrowed,
     author_style_disabled: bool,
+    changed_origins: OriginFlags,
 ) {
     let mut data = PerDocumentStyleData::from_ffi(raw_data).borrow_mut();
-    data.stylesheets.force_dirty();
+    for origin in changed_origins.iter() {
+        data.stylesheets.force_dirty_origin(&origin);
+        data.clear_stylist_origin(&origin);
+    }
     data.stylesheets.set_author_style_disabled(author_style_disabled);
-    data.clear_stylist();
 }
 
 #[no_mangle]