From fc13dd11698524b2b332ad4579fb377a8324248f Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Fri, 7 Aug 2015 18:08:08 -0700
Subject: [PATCH] compositor: Allow children of layers that don't want scroll
 events to be scrolled.

Necessary for `overflow: scroll`.
---
 components/compositing/compositor_layer.rs | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/components/compositing/compositor_layer.rs b/components/compositing/compositor_layer.rs
index 707b7ce06b6..302ac340f09 100644
--- a/components/compositing/compositor_layer.rs
+++ b/components/compositing/compositor_layer.rs
@@ -292,13 +292,7 @@ impl CompositorLayer for Layer<CompositorData> {
                            delta: TypedPoint2D<LayerPixel, f32>,
                            cursor: TypedPoint2D<LayerPixel, f32>)
                            -> ScrollEventResult {
-        // If this layer doesn't want scroll events, neither it nor its children can handle scroll
-        // events.
-        if self.wants_scroll_events() != WantsScrollEventsFlag::WantsScrollEvents {
-            return ScrollEventResult::ScrollEventUnhandled;
-        }
-
-        //// Allow children to scroll.
+        // Allow children to scroll.
         let scroll_offset = self.extra_data.borrow().scroll_offset;
         let new_cursor = cursor - scroll_offset;
         for child in self.children().iter() {
@@ -311,6 +305,11 @@ impl CompositorLayer for Layer<CompositorData> {
             }
         }
 
+        // If this layer doesn't want scroll events, it can't handle scroll events.
+        if self.wants_scroll_events() != WantsScrollEventsFlag::WantsScrollEvents {
+            return ScrollEventResult::ScrollEventUnhandled;
+        }
+
         self.clamp_scroll_offset_and_scroll_layer(scroll_offset + delta)
     }