4 files changed, 27 insertions, 8 deletions
diff --git a/components/layout/Cargo.toml b/components/layout/Cargo.toml
index e3e2c76c2f4..16f82f2236f 100644
--- a/components/layout/Cargo.toml
+++ b/components/layout/Cargo.toml
@@ -34,6 +34,7 @@ script_layout_interface = {path = "../script_layout_interface"}
 script_traits = {path = "../script_traits"}
 selectors = { path = "../selectors" }
 serde = "1.0"
+servo_atoms = {path = "../atoms"}
 servo_geometry = {path = "../geometry"}
 serde_json = "1.0"
 servo_config = {path = "../config"}
diff --git a/components/layout/context.rs b/components/layout/context.rs
index d261fe5d8a7..cda3811421a 100644
--- a/components/layout/context.rs
+++ b/components/layout/context.rs
@@ -4,6 +4,7 @@
 
 //! Data needed by the layout thread.
 
+use fnv::FnvHashMap;
 use fnv::FnvHasher;
 use gfx::display_list::{WebRenderImageInfo, OpaqueNode};
 use gfx::font_cache_thread::FontCacheThread;
@@ -15,8 +16,9 @@ use net_traits::image_cache::{ImageOrMetadataAvailable, UsePlaceholder};
 use opaque_node::OpaqueNodeMethods;
 use parking_lot::RwLock;
 use script_layout_interface::{PendingImage, PendingImageState};
-use script_traits::PaintWorkletExecutor;
+use script_traits::Painter;
 use script_traits::UntrustedNodeAddress;
+use servo_atoms::Atom;
 use servo_url::ServoUrl;
 use std::cell::{RefCell, RefMut};
 use std::collections::HashMap;
@@ -24,6 +26,7 @@ use std::hash::BuildHasherDefault;
 use std::sync::{Arc, Mutex};
 use std::thread;
 use style::context::SharedStyleContext;
+use style::properties::PropertyId;
 
 thread_local!(static FONT_CONTEXT_KEY: RefCell<Option<FontContext>> = RefCell::new(None));
 
@@ -69,8 +72,8 @@ pub struct LayoutContext<'a> {
                                                   WebRenderImageInfo,
                                                   BuildHasherDefault<FnvHasher>>>>,
 
-    /// The executor for worklets
-    pub paint_worklet_executor: Option<Arc<PaintWorkletExecutor>>,
+    /// Paint worklets
+    pub registered_painters: Arc<RwLock<FnvHashMap<Atom, RegisteredPainter>>>,
 
     /// A list of in-progress image loads to be shared with the script thread.
     /// A None value means that this layout was not initiated by the script thread.
@@ -175,3 +178,10 @@ impl<'a> LayoutContext<'a> {
         }
     }
 }
+
+/// A registered paint worklet.
+pub struct RegisteredPainter {
+    pub name: Atom,
+    pub properties: FnvHashMap<Atom, PropertyId>,
+    pub painter: Arc<Painter>,
+}
diff --git a/components/layout/display_list_builder.rs b/components/layout/display_list_builder.rs
index 9aa9301eef8..32439819d9b 100644
--- a/components/layout/display_list_builder.rs
+++ b/components/layout/display_list_builder.rs
@@ -1165,17 +1165,24 @@ impl FragmentDisplayListBuilding for Fragment {
         let size = unbordered_box.size.to_physical(style.writing_mode);
         let name = paint_worklet.name.clone();
 
-        // If the script thread has not added any paint worklet modules, there is nothing to do!
-        let executor = match state.layout_context.paint_worklet_executor {
-            Some(ref executor) => executor,
-            None => return debug!("Worklet {} called before any paint modules are added.", name),
+        // Get the painter, and the computed values for its properties.
+        let (properties, painter) = match state.layout_context.registered_painters.read().get(&name) {
+            Some(registered_painter) => (
+                registered_painter.properties
+                    .iter()
+                    .filter_map(|(name, id)| id.as_shorthand().err().map(|id| (name, id)))
+                    .map(|(name, id)| (name.clone(), style.computed_value_to_string(id)))
+                    .collect(),
+                registered_painter.painter.clone()
+            ),
+            None => return debug!("Worklet {} called before registration.", name),
         };
 
         // TODO: add a one-place cache to avoid drawing the paint image every time.
         // https://github.com/servo/servo/issues/17369
         debug!("Drawing a paint image {}({},{}).", name, size.width.to_px(), size.height.to_px());
         let (sender, receiver) = ipc::channel().unwrap();
-        executor.draw_a_paint_image(name, size, sender);
+        painter.draw_a_paint_image(size, properties, sender);
 
         // TODO: timeout
         let webrender_image = match receiver.recv() {
diff --git a/components/layout/lib.rs b/components/layout/lib.rs
index af108249c42..f7ed79be750 100644
--- a/components/layout/lib.rs
+++ b/components/layout/lib.rs
@@ -37,6 +37,7 @@ extern crate script_layout_interface;
 extern crate script_traits;
 #[macro_use] extern crate serde;
 extern crate serde_json;
+extern crate servo_atoms;
 extern crate servo_config;
 extern crate servo_geometry;
 extern crate servo_url;