init support of smooth

components/msg/compositor_msg.rs

@@ -139,7 +139,8 @@ impl ScriptListener {
     pub fn scroll_fragment_point(&mut self,
                                  pipeline_id: PipelineId,
                                  layer_id: LayerId,
-                                 point: Point2D<f32>) {
+                                 point: Point2D<f32>,
+                                 _: bool) {
         self.0
             .send(ScriptToCompositorMsg::ScrollFragmentPoint(pipeline_id, layer_id, point))
             .unwrap()

components/script/dom/window.rs

@@ -901,10 +901,15 @@ impl<'a> WindowHelpers for &'a Window {
     }
 
     /// https://drafts.csswg.org/cssom-view/#perform-a-scroll
-    fn perform_a_scroll(self, x: f32, y: f32, _: ScrollBehavior) {
+    fn perform_a_scroll(self, x: f32, y: f32, behavior: ScrollBehavior) {
         //TODO Step 1
         let point = Point2D::new(x, y);
-        self.compositor.borrow_mut().scroll_fragment_point(self.pipeline(), LayerId::null(), point)
+        let smooth = match behavior {
+            ScrollBehavior::Auto => false,
+            ScrollBehavior::Instant => false,
+            ScrollBehavior::Smooth => true
+        };
+        self.compositor.borrow_mut().scroll_fragment_point(self.pipeline(), LayerId::null(), point, smooth)
     }
 
     /// Reflows the page unconditionally. This method will wait for the layout thread to complete

components/script/script_task.rs

@@ -1559,7 +1559,7 @@ impl ScriptTask {
         // Really what needs to happen is that this needs to go through layout to ask which
         // layer the element belongs to, and have it send the scroll message to the
         // compositor.
-        self.compositor.borrow_mut().scroll_fragment_point(pipeline_id, LayerId::null(), point);
+        self.compositor.borrow_mut().scroll_fragment_point(pipeline_id, LayerId::null(), point, false);
     }
 
     /// Reflows non-incrementally, rebuilding the entire layout tree in the process.