chore: Clean up use of `gfx` and `constellation` types (#31981)

This change contains three semi-related clean ups:

1. the `to_webrender()` and `from_webrender()` functions on Pipeline are
   turned into more-idiomatic `From` and `Into` implementations.
2. `combine_id_with_fragment_type` now returns a `u64` as that is what is
   expected for all callers and not a `usize`.
3. The `query_scroll_id` query is removed entirely. The
   `ExternalScrollId` that this queries is easily generated directly
   from the node's opaque id. Querying into layout isn't necessary at
   all.

3 files changed, 2 insertions, 12 deletions

diff --git a/components/shared/script_layout/lib.rs b/components/shared/script_layout/lib.rs
index 3279f993820..20d8c982dc2 100644
--- a/components/shared/script_layout/lib.rs
+++ b/components/shared/script_layout/lib.rs
@@ -46,7 +46,7 @@ use style::properties::PropertyId;
 use style::selector_parser::PseudoElement;
 use style::stylesheets::Stylesheet;
 use style_traits::CSSPixel;
-use webrender_api::{ExternalScrollId, ImageKey};
+use webrender_api::ImageKey;
 
 pub type GenericLayoutData = dyn Any + Send + Sync;
 
@@ -235,7 +235,6 @@ pub trait Layout {
         animations: DocumentAnimationSet,
         animation_timeline_value: f64,
     ) -> Option<ServoArc<Font>>;
-    fn query_scroll_id(&self, node: TrustedNodeAddress) -> ExternalScrollId;
     fn query_scrolling_area(&self, node: Option<OpaqueNode>) -> Rect<i32>;
     fn query_text_indext(&self, node: OpaqueNode, point: Point2D<f32>) -> Option<usize>;
 }
diff --git a/components/shared/script_layout/message.rs b/components/shared/script_layout/message.rs
index 34de65cd227..018e554e893 100644
--- a/components/shared/script_layout/message.rs
+++ b/components/shared/script_layout/message.rs
@@ -55,7 +55,6 @@ pub enum QueryMsg {
     OffsetParentQuery,
     TextIndexQuery,
     NodesFromPointQuery,
-    NodeScrollIdQuery,
     ResolvedStyleQuery,
     StyleQuery,
     ElementInnerTextQuery,
@@ -90,7 +89,6 @@ impl ReflowGoal {
                 QueryMsg::ClientRectQuery |
                 QueryMsg::ContentBox |
                 QueryMsg::ContentBoxes |
-                QueryMsg::NodeScrollIdQuery |
                 QueryMsg::OffsetParentQuery |
                 QueryMsg::ResolvedFontStyleQuery |
                 QueryMsg::ScrollingAreaQuery |
@@ -112,7 +110,6 @@ impl ReflowGoal {
                 QueryMsg::ContentBoxes |
                 QueryMsg::ClientRectQuery |
                 QueryMsg::ScrollingAreaQuery |
-                QueryMsg::NodeScrollIdQuery |
                 QueryMsg::ResolvedStyleQuery |
                 QueryMsg::ResolvedFontStyleQuery |
                 QueryMsg::OffsetParentQuery |
diff --git a/components/shared/script_layout/wrapper_traits.rs b/components/shared/script_layout/wrapper_traits.rs
index c1bd1fc4d95..846943414ae 100644
--- a/components/shared/script_layout/wrapper_traits.rs
+++ b/components/shared/script_layout/wrapper_traits.rs
@@ -9,7 +9,7 @@ use std::fmt::Debug;
 use std::sync::Arc as StdArc;
 
 use atomic_refcell::AtomicRef;
-use gfx_traits::{combine_id_with_fragment_type, ByteIndex, FragmentType};
+use gfx_traits::{ByteIndex, FragmentType};
 use html5ever::{local_name, namespace_url, ns, LocalName, Namespace};
 use msg::constellation_msg::{BrowsingContextId, PipelineId};
 use net_traits::image::base::{Image, ImageMetadata};
@@ -23,7 +23,6 @@ use style::dom::{LayoutIterator, NodeInfo, OpaqueNode, TElement, TNode};
 use style::properties::ComputedValues;
 use style::selector_parser::{PseudoElement, PseudoElementCascadeType, SelectorImpl};
 use style::stylist::RuleInclusion;
-use webrender_api::ExternalScrollId;
 
 use crate::{
     GenericLayoutData, HTMLCanvasData, HTMLMediaData, LayoutNodeType, SVGSVGData, StyleData,
@@ -315,11 +314,6 @@ pub trait ThreadSafeLayoutNode<'dom>: Clone + Copy + Debug + NodeInfo + PartialE
     fn fragment_type(&self) -> FragmentType {
         self.get_pseudo_element_type().fragment_type()
     }
-
-    fn generate_scroll_id(&self, pipeline_id: PipelineId) -> ExternalScrollId {
-        let id = combine_id_with_fragment_type(self.opaque().id(), self.fragment_type());
-        ExternalScrollId(id as u64, pipeline_id.to_webrender())
-    }
 }
 
 pub trait ThreadSafeLayoutElement<'dom>: