diff --git a/components/layout_thread/dom_wrapper.rs b/components/layout_thread/dom_wrapper.rs
index d211ab88063..d1eb7a1b2da 100644
--- a/components/layout_thread/dom_wrapper.rs
+++ b/components/layout_thread/dom_wrapper.rs
@@ -38,7 +38,7 @@ use layout::data::StyleAndLayoutData;
 use layout::wrapper::GetRawData;
 use msg::constellation_msg::{BrowsingContextId, PipelineId};
 use range::Range;
-use script::layout_exports::{CAN_BE_FRAGMENTED, DIRTY_ON_VIEWPORT_SIZE_CHANGE, HAS_DIRTY_DESCENDANTS, IS_IN_DOC};
+use script::layout_exports::{CAN_BE_FRAGMENTED, HAS_DIRTY_DESCENDANTS, IS_IN_DOC};
 use script::layout_exports::{CharacterDataTypeId, ElementTypeId, HTMLElementTypeId, NodeTypeId};
 use script::layout_exports::{Document, Element, Node, Text};
 use script::layout_exports::{HANDLED_SNAPSHOT, HAS_SNAPSHOT};
@@ -205,14 +205,6 @@ impl<'ln> TNode for ServoLayoutNode<'ln> {
         as_element(self.node)
     }
 
-    fn needs_dirty_on_viewport_size_changed(&self) -> bool {
-        unsafe { self.node.get_flag(DIRTY_ON_VIEWPORT_SIZE_CHANGE) }
-    }
-
-    unsafe fn set_dirty_on_viewport_size_changed(&self) {
-        self.node.set_flag(DIRTY_ON_VIEWPORT_SIZE_CHANGE, true);
-    }
-
     fn can_be_fragmented(&self) -> bool {
         unsafe { self.node.get_flag(CAN_BE_FRAGMENTED) }
     }
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 03719528655..b83cdcbd37e 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -169,8 +169,7 @@ bitflags! {
         /// Whether any ancestor is a fragmentation container
         const CAN_BE_FRAGMENTED = 1 << 4,
 
-        #[doc = "Specifies whether this node needs to be dirted when viewport size changed."]
-        const DIRTY_ON_VIEWPORT_SIZE_CHANGE = 1 << 5,
+        // There's a free bit here.
 
         #[doc = "Specifies whether the parser has set an associated form owner for \
                  this element. Only applicable for form-associatable elements."]
diff --git a/components/script/lib.rs b/components/script/lib.rs
index 223f00d33c2..5ba671440bd 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -142,7 +142,7 @@ pub mod layout_exports {
     pub use dom::characterdata::LayoutCharacterDataHelpers;
     pub use dom::document::{Document, LayoutDocumentHelpers, PendingRestyle};
     pub use dom::element::{Element, LayoutElementHelpers, RawLayoutElementHelpers};
-    pub use dom::node::{CAN_BE_FRAGMENTED, DIRTY_ON_VIEWPORT_SIZE_CHANGE, HAS_DIRTY_DESCENDANTS, IS_IN_DOC};
+    pub use dom::node::{CAN_BE_FRAGMENTED, HAS_DIRTY_DESCENDANTS, IS_IN_DOC};
     pub use dom::node::{HANDLED_SNAPSHOT, HAS_SNAPSHOT};
     pub use dom::node::{LayoutNodeHelpers, Node};
     pub use dom::text::Text;
diff --git a/components/style/dom.rs b/components/style/dom.rs
index 60046312c89..9c1f8f44a2e 100644
--- a/components/style/dom.rs
+++ b/components/style/dom.rs
@@ -138,12 +138,6 @@ pub trait TNode : Sized + Copy + Clone + Debug + NodeInfo {
     /// Get this node as an element, if it's one.
     fn as_element(&self) -> Option<Self::ConcreteElement>;
 
-    /// Whether this node needs to be laid out on viewport size change.
-    fn needs_dirty_on_viewport_size_changed(&self) -> bool;
-
-    /// Mark this node as needing layout on viewport size change.
-    unsafe fn set_dirty_on_viewport_size_changed(&self);
-
     /// Whether this node can be fragmented. This is used for multicol, and only
     /// for Servo.
     fn can_be_fragmented(&self) -> bool;
diff --git a/components/style/gecko/wrapper.rs b/components/style/gecko/wrapper.rs
index 305543813d7..7883d9dd891 100644
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@@ -318,17 +318,6 @@ impl<'ln> TNode for GeckoNode<'ln> {
     fn is_in_doc(&self) -> bool {
         unsafe { bindings::Gecko_IsInDocument(self.0) }
     }
-
-    fn needs_dirty_on_viewport_size_changed(&self) -> bool {
-        // Gecko's node doesn't have the DIRTY_ON_VIEWPORT_SIZE_CHANGE flag,
-        // so we force them to be dirtied on viewport size change, regardless if
-        // they use viewport percentage size or not.
-        // TODO(shinglyu): implement this in Gecko: https://github.com/servo/servo/pull/11890
-        true
-    }
-
-    // TODO(shinglyu): implement this in Gecko: https://github.com/servo/servo/pull/11890
-    unsafe fn set_dirty_on_viewport_size_changed(&self) {}
 }
 
 /// A wrapper on top of two kind of iterators, depending on the parent being