Auto merge of #12777 - emilio:hit-test, r=pcwalton

layout: Take into account the client point for fixed positioned stacking contexts

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #12763 (github issue number if applicable).

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- [ ] These changes do not require tests because _____

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components/script_layout_interface/message.rs

@@ -98,7 +98,7 @@ pub enum ReflowQueryType {
     ContentBoxQuery(TrustedNodeAddress),
     ContentBoxesQuery(TrustedNodeAddress),
     NodeOverflowQuery(TrustedNodeAddress),
-    HitTestQuery(Point2D<f32>, bool),
+    HitTestQuery(Point2D<f32>, Point2D<f32>, bool),
     NodeGeometryQuery(TrustedNodeAddress),
     NodeLayerIdQuery(TrustedNodeAddress),
     NodeScrollGeometryQuery(TrustedNodeAddress),

components/script_layout_interface/rpc.rs

@@ -38,7 +38,7 @@ pub trait LayoutRPC {
     /// Query layout for the resolve values of the margin properties for an element.
     fn margin_style(&self) -> MarginStyleResponse;
 
-    fn nodes_from_point(&self, point: Point2D<f32>) -> Vec<UntrustedNodeAddress>;
+    fn nodes_from_point(&self, page_point: Point2D<f32>, client_point: Point2D<f32>) -> Vec<UntrustedNodeAddress>;
 }
 
 pub struct ContentBoxResponse(pub Rect<Au>);