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.

components/shared/gfx/lib.rs

@@ -8,7 +8,7 @@
 
 pub mod print_tree;
 
-use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::atomic::{AtomicU64, Ordering};
 
 use malloc_size_of_derive::MallocSizeOf;
 use range::{int_range_index, RangeIndex};
@@ -90,30 +90,30 @@ pub enum FragmentType {
 /// The next ID that will be used for a special scroll root id.
 ///
 /// A special scroll root is a scroll root that is created for generated content.
-static NEXT_SPECIAL_SCROLL_ROOT_ID: AtomicUsize = AtomicUsize::new(0);
+static NEXT_SPECIAL_SCROLL_ROOT_ID: AtomicU64 = AtomicU64::new(0);
 
 /// If none of the bits outside this mask are set, the scroll root is a special scroll root.
 /// Note that we assume that the top 16 bits of the address space are unused on the platform.
-const SPECIAL_SCROLL_ROOT_ID_MASK: usize = 0xffff;
+const SPECIAL_SCROLL_ROOT_ID_MASK: u64 = 0xffff;
 
 /// Returns a new scroll root ID for a scroll root.
-fn next_special_id() -> usize {
+fn next_special_id() -> u64 {
     // We shift this left by 2 to make room for the fragment type ID.
     ((NEXT_SPECIAL_SCROLL_ROOT_ID.fetch_add(1, Ordering::SeqCst) + 1) << 2) &
         SPECIAL_SCROLL_ROOT_ID_MASK
 }
 
-pub fn combine_id_with_fragment_type(id: usize, fragment_type: FragmentType) -> usize {
+pub fn combine_id_with_fragment_type(id: usize, fragment_type: FragmentType) -> u64 {
     debug_assert_eq!(id & (fragment_type as usize), 0);
     if fragment_type == FragmentType::FragmentBody {
-        id
+        id as u64
     } else {
-        next_special_id() | (fragment_type as usize)
+        next_special_id() | (fragment_type as u64)
     }
 }
 
 pub fn node_id_from_scroll_id(id: usize) -> Option<usize> {
-    if (id & !SPECIAL_SCROLL_ROOT_ID_MASK) != 0 {
+    if (id as u64 & !SPECIAL_SCROLL_ROOT_ID_MASK) != 0 {
         return Some(id & !3);
     }
     None

components/shared/msg/constellation_msg.rs

@@ -223,14 +223,14 @@ impl PipelineId {
         })
     }
 
-    pub fn to_webrender(&self) -> WebRenderPipelineId {
-        let PipelineNamespaceId(namespace_id) = self.namespace_id;
-        let PipelineIndex(index) = self.index;
-        WebRenderPipelineId(namespace_id, index.get())
+    pub fn root_scroll_id(&self) -> webrender_api::ExternalScrollId {
+        ExternalScrollId(0, self.into())
     }
+}
 
+impl From<WebRenderPipelineId> for PipelineId {
     #[allow(unsafe_code)]
-    pub fn from_webrender(pipeline: WebRenderPipelineId) -> PipelineId {
+    fn from(pipeline: WebRenderPipelineId) -> Self {
         let WebRenderPipelineId(namespace_id, index) = pipeline;
         unsafe {
             PipelineId {
@@ -239,9 +239,19 @@ impl PipelineId {
             }
         }
     }
+}
 
-    pub fn root_scroll_id(&self) -> webrender_api::ExternalScrollId {
-        ExternalScrollId(0, self.to_webrender())
+impl From<PipelineId> for WebRenderPipelineId {
+    fn from(value: PipelineId) -> Self {
+        let PipelineNamespaceId(namespace_id) = value.namespace_id;
+        let PipelineIndex(index) = value.index;
+        WebRenderPipelineId(namespace_id, index.get())
+    }
+}
+
+impl From<&PipelineId> for WebRenderPipelineId {
+    fn from(value: &PipelineId) -> Self {
+        (*value).into()
     }
 }
 

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>;
 }

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 |

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>: