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.

1 files changed, 2 insertions, 2 deletions

diff --git a/components/layout/display_list/webrender_helpers.rs b/components/layout/display_list/webrender_helpers.rs
index fb5159b5cf0..85c3694b98d 100644
--- a/components/layout/display_list/webrender_helpers.rs
+++ b/components/layout/display_list/webrender_helpers.rs
@@ -133,7 +133,7 @@ impl DisplayList {
         viewport_size: LayoutSize,
         epoch: Epoch,
     ) -> (DisplayListBuilder, CompositorDisplayListInfo, IsContentful) {
-        let webrender_pipeline = pipeline_id.to_webrender();
+        let webrender_pipeline = pipeline_id.into();
         let mut builder = DisplayListBuilder::new(webrender_pipeline);
         builder.begin();
 
@@ -314,7 +314,7 @@ impl DisplayItem {
                         spatial_id: common.spatial_id,
                         clip_chain_id: common.clip_chain_id,
                     },
-                    item.iframe.to_webrender(),
+                    item.iframe.into(),
                     true,
                 );
                 IsContentful(false)