diff --git a/servo/components/style/dom.rs b/servo/components/style/dom.rs
index d2ed5ae3d99e..7df9c850fd42 100644
--- a/servo/components/style/dom.rs
+++ b/servo/components/style/dom.rs
@@ -462,6 +462,28 @@ pub trait TElement : Eq + PartialEq + Debug + Hash + Sized + Copy + Clone +
         data.has_styles() && !data.restyle.hint.has_non_animation_invalidations()
     }
 
+    /// Returns whether the element's styles are up-to-date after traversal
+    /// (i.e. in post traversal).
+    fn has_current_styles(&self, data: &ElementData) -> bool {
+        if self.has_snapshot() && !self.handled_snapshot() {
+            return false;
+        }
+
+        data.has_styles() &&
+        // TODO(hiro): When an animating element moved into subtree of
+        // contenteditable element, there remains animation restyle hints in
+        // post traversal. It's generally harmless since the hints will be
+        // processed in a next styling but ideally it should be processed soon.
+        //
+        // Without this, we get failures in:
+        //   layout/style/crashtests/1383319.html
+        //   layout/style/crashtests/1383001.html
+        //
+        // https://bugzilla.mozilla.org/show_bug.cgi?id=1389675 tracks fixing
+        // this.
+        !data.restyle.hint.has_non_animation_invalidations()
+    }
+
     /// Flag that this element has a descendant for style processing.
     ///
     /// Only safe to call with exclusive access to the element.
diff --git a/servo/components/style/gecko/generated/bindings.rs b/servo/components/style/gecko/generated/bindings.rs
index 86d0d7638997..e9e012a3a892 100644
--- a/servo/components/style/gecko/generated/bindings.rs
+++ b/servo/components/style/gecko/generated/bindings.rs
@@ -2815,13 +2815,11 @@ extern "C" {
 }
 extern "C" {
     pub fn Servo_TakeChangeHint(element: RawGeckoElementBorrowed,
-                                flags: ServoTraversalFlags,
                                 was_restyled: *mut bool) -> nsChangeHint;
 }
 extern "C" {
     pub fn Servo_ResolveStyle(element: RawGeckoElementBorrowed,
-                              set: RawServoStyleSetBorrowed,
-                              flags: ServoTraversalFlags)
+                              set: RawServoStyleSetBorrowed)
      -> ServoStyleContextStrong;
 }
 extern "C" {
diff --git a/servo/components/style/gecko/generated/structs_debug.rs b/servo/components/style/gecko/generated/structs_debug.rs
index 1a871409077d..ead3685edd3a 100644
--- a/servo/components/style/gecko/generated/structs_debug.rs
+++ b/servo/components/style/gecko/generated/structs_debug.rs
@@ -4944,6 +4944,9 @@ pub mod root {
         pub const ServoTraversalFlags_ParallelTraversal:
                   root::mozilla::ServoTraversalFlags =
             128;
+        pub const ServoTraversalFlags_FlushThrottledAnimations:
+                  root::mozilla::ServoTraversalFlags =
+            256;
         pub type ServoTraversalFlags = u32;
         #[repr(i32)]
         #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -6644,12 +6647,6 @@ pub mod root {
             Standard = 1,
             Layer = 2,
         }
-        #[repr(i32)]
-        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
-        pub enum EffectCompositor_AnimationRestyleType {
-            Throttled = 0,
-            Full = 1,
-        }
         #[repr(C)]
         #[derive(Debug)]
         pub struct EffectCompositor_AnimationStyleRuleProcessor {
@@ -33560,7 +33557,7 @@ pub mod root {
                    root::nsTArray<root::mozilla::gfx::FontVariation> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_200547_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_200542_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsCSSSelector>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -33916,7 +33913,7 @@ pub mod root {
                    root::mozilla::binding_danger::TErrorResult ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_202364_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_202359_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34077,7 +34074,7 @@ pub mod root {
                    root::JS::DeletePolicy ) ));
     }
     #[test]
-    fn __bindgen_test_layout_iterator_open0_input_iterator_tag_UniquePtr_open1_JSErrorNotes_Note_DeletePolicy_open2_JSErrorNotes_Note_close2_close1_long__bindgen_ty_id_207983__bindgen_ty_id_207990_close0_instantiation() {
+    fn __bindgen_test_layout_iterator_open0_input_iterator_tag_UniquePtr_open1_JSErrorNotes_Note_DeletePolicy_open2_JSErrorNotes_Note_close2_close1_long__bindgen_ty_id_207978__bindgen_ty_id_207985_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::std::iterator>() , 1usize ,
                    concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34303,7 +34300,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::StyleSheet> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210468_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210463_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::Element>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34371,7 +34368,7 @@ pub mod root {
                    root::nsCOMPtr<root::nsIObserver> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210770_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210765_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::Element>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34483,7 +34480,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::URLExtraData> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_NotNull_open0__bindgen_ty_id_211312_close0_instantiation() {
+    fn __bindgen_test_layout_NotNull_open0__bindgen_ty_id_211307_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::mozilla::NotNull<*const root::mozilla::Encoding>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34865,7 +34862,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::StyleSheet> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_211727_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_211722_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34955,7 +34952,7 @@ pub mod root {
                    ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_212126_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_212121_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35056,7 +35053,7 @@ pub mod root {
                    root::nsTArray<::nsstring::nsStringRepr> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213091_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213085_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35145,7 +35142,7 @@ pub mod root {
                    root::RefPtr<root::nsCSSFontFaceRule> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213396_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213390_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35156,7 +35153,7 @@ pub mod root {
                    root::nsTArray<*mut root::nsIContent> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213401_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213395_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35213,7 +35210,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::CSSStyleSheet> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213892_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_213886_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35861,7 +35858,7 @@ pub mod root {
                    root::nsCOMPtr<root::nsIWeakReference> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_216753_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_216747_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut ::std::os::raw::c_void>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35940,7 +35937,7 @@ pub mod root {
                    root::mozilla::DefaultDelete ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_223015_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_223009_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::AudioContext>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35973,7 +35970,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::dom::CallbackObject> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_224176_close0_instantiation() {
+    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_224170_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::JS::Heap<*mut root::JSObject>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35984,7 +35981,7 @@ pub mod root {
                    root::JS::Heap<*mut root::JSObject> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_224180_close0_instantiation() {
+    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_224174_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::JS::Heap<*mut root::JSObject>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36006,7 +36003,7 @@ pub mod root {
                    root::nsCOMPtr<root::nsIGlobalObject> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_TenuredHeap_open0__bindgen_ty_id_224187_close0_instantiation() {
+    fn __bindgen_test_layout_TenuredHeap_open0__bindgen_ty_id_224181_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::JS::TenuredHeap>() , 8usize ,
                    concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36085,7 +36082,7 @@ pub mod root {
                    ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_225360_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_225354_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsISupports>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36280,7 +36277,7 @@ pub mod root {
                    root::nsTArray<f64> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_226808_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_226802_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::Element>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36385,7 +36382,7 @@ pub mod root {
                    root::nsRefPtrHashKey<root::nsIAtom> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_229231_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_229225_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::CounterStyle>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37086,7 +37083,7 @@ pub mod root {
                    root::RefPtr<root::nsStyleImageRequest> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_231784_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_231778_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsISupports>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37323,7 +37320,7 @@ pub mod root {
                    root::nsCOMPtr<root::nsIURI> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_239592_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_239586_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37334,7 +37331,7 @@ pub mod root {
                    root::nsTArray<*mut root::nsIContent> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_239597_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_239591_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37422,7 +37419,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::dom::ShadowRoot> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_239710_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_239704_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37709,7 +37706,7 @@ pub mod root {
                    ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_241296_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_241290_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37731,7 +37728,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::dom::Element> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_241458_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_241452_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37742,7 +37739,7 @@ pub mod root {
                    root::nsTArray<*mut root::nsIContent> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_241463_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_241457_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37874,7 +37871,7 @@ pub mod root {
                    root::nsTArray<root::mozilla::gfx::FontVariation> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_243547_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_243541_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::css::DocumentRule>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37885,7 +37882,7 @@ pub mod root {
                    root::nsTArray<*mut root::mozilla::css::DocumentRule> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_243555_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_243549_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::css::DocumentRule>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
diff --git a/servo/components/style/gecko/generated/structs_release.rs b/servo/components/style/gecko/generated/structs_release.rs
index d726fa9f8270..be299f97ee74 100644
--- a/servo/components/style/gecko/generated/structs_release.rs
+++ b/servo/components/style/gecko/generated/structs_release.rs
@@ -4832,6 +4832,9 @@ pub mod root {
         pub const ServoTraversalFlags_ParallelTraversal:
                   root::mozilla::ServoTraversalFlags =
             128;
+        pub const ServoTraversalFlags_FlushThrottledAnimations:
+                  root::mozilla::ServoTraversalFlags =
+            256;
         pub type ServoTraversalFlags = u32;
         #[repr(i32)]
         #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -6524,12 +6527,6 @@ pub mod root {
             Standard = 1,
             Layer = 2,
         }
-        #[repr(i32)]
-        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
-        pub enum EffectCompositor_AnimationRestyleType {
-            Throttled = 0,
-            Full = 1,
-        }
         #[repr(C)]
         #[derive(Debug)]
         pub struct EffectCompositor_AnimationStyleRuleProcessor {
@@ -33068,7 +33065,7 @@ pub mod root {
                    root::nsTArray<root::mozilla::gfx::FontVariation> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_198186_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_198181_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsCSSSelector>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -33424,7 +33421,7 @@ pub mod root {
                    root::mozilla::binding_danger::TErrorResult ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_199969_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_199964_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -33585,7 +33582,7 @@ pub mod root {
                    root::JS::DeletePolicy ) ));
     }
     #[test]
-    fn __bindgen_test_layout_iterator_open0_input_iterator_tag_UniquePtr_open1_JSErrorNotes_Note_DeletePolicy_open2_JSErrorNotes_Note_close2_close1_long__bindgen_ty_id_205560__bindgen_ty_id_205567_close0_instantiation() {
+    fn __bindgen_test_layout_iterator_open0_input_iterator_tag_UniquePtr_open1_JSErrorNotes_Note_DeletePolicy_open2_JSErrorNotes_Note_close2_close1_long__bindgen_ty_id_205555__bindgen_ty_id_205562_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::std::iterator>() , 1usize ,
                    concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -33811,7 +33808,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::StyleSheet> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_208043_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_208038_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::Element>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -33879,7 +33876,7 @@ pub mod root {
                    root::nsCOMPtr ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_208345_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_208340_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::Element>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -33991,7 +33988,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::URLExtraData> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_NotNull_open0__bindgen_ty_id_208887_close0_instantiation() {
+    fn __bindgen_test_layout_NotNull_open0__bindgen_ty_id_208882_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::mozilla::NotNull<*const root::mozilla::Encoding>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34371,7 +34368,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::StyleSheet> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_209300_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_209295_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34461,7 +34458,7 @@ pub mod root {
                    ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_209697_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_209692_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34562,7 +34559,7 @@ pub mod root {
                    root::nsTArray<::nsstring::nsStringRepr> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210652_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210646_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34651,7 +34648,7 @@ pub mod root {
                    root::RefPtr<root::nsCSSFontFaceRule> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210955_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210949_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34662,7 +34659,7 @@ pub mod root {
                    root::nsTArray<*mut root::nsIContent> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210960_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_210954_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -34719,7 +34716,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::CSSStyleSheet> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_211435_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_211429_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::StyleSheet>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35354,7 +35351,7 @@ pub mod root {
                    root::nsCOMPtr ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_214266_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_214260_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut ::std::os::raw::c_void>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35433,7 +35430,7 @@ pub mod root {
                    root::mozilla::DefaultDelete ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_220511_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_220505_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::AudioContext>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35466,7 +35463,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::dom::CallbackObject> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_221672_close0_instantiation() {
+    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_221666_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::JS::Heap<*mut root::JSObject>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35477,7 +35474,7 @@ pub mod root {
                    root::JS::Heap<*mut root::JSObject> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_221676_close0_instantiation() {
+    fn __bindgen_test_layout_Heap_open0__bindgen_ty_id_221670_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::JS::Heap<*mut root::JSObject>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35499,7 +35496,7 @@ pub mod root {
                    root::nsCOMPtr ) ));
     }
     #[test]
-    fn __bindgen_test_layout_TenuredHeap_open0__bindgen_ty_id_221683_close0_instantiation() {
+    fn __bindgen_test_layout_TenuredHeap_open0__bindgen_ty_id_221677_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::JS::TenuredHeap>() , 8usize ,
                    concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35578,7 +35575,7 @@ pub mod root {
                    ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_222856_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_222850_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsISupports>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35773,7 +35770,7 @@ pub mod root {
                    root::nsTArray<f64> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_224304_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_224298_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::dom::Element>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -35878,7 +35875,7 @@ pub mod root {
                    root::nsRefPtrHashKey<root::nsIAtom> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_226692_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_226686_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::CounterStyle>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36579,7 +36576,7 @@ pub mod root {
                    root::RefPtr<root::nsStyleImageRequest> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_229169_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_229163_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsISupports>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36816,7 +36813,7 @@ pub mod root {
                    root::nsCOMPtr ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_236977_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_236971_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36827,7 +36824,7 @@ pub mod root {
                    root::nsTArray<*mut root::nsIContent> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_236982_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_236976_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -36915,7 +36912,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::dom::ShadowRoot> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_237095_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_237089_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37202,7 +37199,7 @@ pub mod root {
                    ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_238675_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_238669_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37224,7 +37221,7 @@ pub mod root {
                    root::RefPtr<root::mozilla::dom::Element> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_238833_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_238827_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37235,7 +37232,7 @@ pub mod root {
                    root::nsTArray<*mut root::nsIContent> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_238838_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_238832_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::nsIContent>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37367,7 +37364,7 @@ pub mod root {
                    root::nsTArray<root::mozilla::gfx::FontVariation> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_240912_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_240906_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::css::DocumentRule>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
@@ -37378,7 +37375,7 @@ pub mod root {
                    root::nsTArray<*mut root::mozilla::css::DocumentRule> ) ));
     }
     #[test]
-    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_240918_close0_instantiation() {
+    fn __bindgen_test_layout_nsTArray_open0__bindgen_ty_id_240912_close0_instantiation() {
         assert_eq!(::std::mem::size_of::<root::nsTArray<*mut root::mozilla::css::DocumentRule>>()
                    , 8usize , concat ! (
                    "Size of template specialization: " , stringify ! (
diff --git a/servo/components/style/traversal_flags.rs b/servo/components/style/traversal_flags.rs
index 2e3e0f4c2ad3..473b576a4563 100644
--- a/servo/components/style/traversal_flags.rs
+++ b/servo/components/style/traversal_flags.rs
@@ -34,6 +34,10 @@ bitflags! {
         /// Allows the traversal to run in parallel if there are sufficient cores on
         /// the machine.
         const ParallelTraversal = 1 << 7,
+        /// Flush throttled animations. By default, we only update throttled animations
+        /// when we have other non-throttled work to do. With this flag, we
+        /// unconditionally tick and process them.
+        const FlushThrottledAnimations = 1 << 8,
 
     }
 }
@@ -67,6 +71,7 @@ pub fn assert_traversal_flags_match() {
         ServoTraversalFlags_ClearAnimationOnlyDirtyDescendants =>
             ClearAnimationOnlyDirtyDescendants,
         ServoTraversalFlags_ParallelTraversal => ParallelTraversal,
+        ServoTraversalFlags_FlushThrottledAnimations => FlushThrottledAnimations,
     }
 }
 
diff --git a/servo/ports/geckolib/glue.rs b/servo/ports/geckolib/glue.rs
index 0d0ff0db9bea..d20fce6fb139 100644
--- a/servo/ports/geckolib/glue.rs
+++ b/servo/ports/geckolib/glue.rs
@@ -278,13 +278,6 @@ pub extern "C" fn Servo_TraverseSubtree(root: RawGeckoElementBorrowed,
         }
     }
 
-    if traversal_flags.for_animation_only() {
-        debug!("Servo_TraverseSubtree complete (animation-only, aodd={})",
-               element.has_animation_only_dirty_descendants());
-        return element.has_animation_only_dirty_descendants() ||
-               element.borrow_data().unwrap().restyle.is_restyle();
-    }
-
     traverse_subtree(element,
                      raw_data,
                      traversal_flags,
@@ -2782,10 +2775,8 @@ pub extern "C" fn Servo_NoteExplicitHints(element: RawGeckoElementBorrowed,
 
 #[no_mangle]
 pub extern "C" fn Servo_TakeChangeHint(element: RawGeckoElementBorrowed,
-                                       raw_flags: ServoTraversalFlags,
                                        was_restyled: *mut bool) -> nsChangeHint
 {
-    let flags = TraversalFlags::from_bits_truncate(raw_flags);
     let mut was_restyled =  unsafe { was_restyled.as_mut().unwrap() };
     let element = GeckoElement(element);
 
@@ -2794,25 +2785,7 @@ pub extern "C" fn Servo_TakeChangeHint(element: RawGeckoElementBorrowed,
             *was_restyled = data.restyle.is_restyle();
 
             let damage = data.restyle.damage;
-            if flags.for_animation_only() {
-                if !*was_restyled {
-                    // Don't touch elements if the element was not restyled
-                    // in throttled animation flush.
-                    debug!("Skip post traversal for throttled animation flush {:?} restyle={:?}",
-                           element, data.restyle);
-                    return nsChangeHint(0);
-                }
-                // In the case where we call this function for post traversal for
-                // flusing throttled animations (i.e. without normal restyle
-                // traversal), we need to preserve restyle hints for normal restyle
-                // traversal. Restyle hints for animations have been already
-                // removed during animation-only traversal.
-                debug_assert!(!data.restyle.hint.has_animation_hint(),
-                              "Animation restyle hints should have been already removed");
-                data.clear_restyle_flags_and_damage();
-            } else {
-                data.clear_restyle_state();
-            }
+            data.clear_restyle_state();
             damage
         }
         None => {
@@ -2828,11 +2801,9 @@ pub extern "C" fn Servo_TakeChangeHint(element: RawGeckoElementBorrowed,
 
 #[no_mangle]
 pub extern "C" fn Servo_ResolveStyle(element: RawGeckoElementBorrowed,
-                                     _raw_data: RawServoStyleSetBorrowed,
-                                     raw_flags: ServoTraversalFlags)
+                                     _raw_data: RawServoStyleSetBorrowed)
                                      -> ServoStyleContextStrong
 {
-    let flags = TraversalFlags::from_bits_truncate(raw_flags);
     let element = GeckoElement(element);
     debug!("Servo_ResolveStyle: {:?}", element);
     let data =
@@ -2840,9 +2811,7 @@ pub extern "C" fn Servo_ResolveStyle(element: RawGeckoElementBorrowed,
 
     // TODO(emilio): Downgrade to debug assertions when close to release.
     assert!(data.has_styles(), "Resolving style on unstyled element");
-    // In the case where we process for throttled animation, there remaings
-    // restyle hints other than animation hints.
-    debug_assert!(element.has_current_styles_for_traversal(&*data, flags),
+    debug_assert!(element.has_current_styles(&*data),
                   "Resolving style on {:?} without current styles: {:?}", element, data);
     data.styles.primary().clone().into()
 }