constellation: Proxy ScrollState through the Constellation (#36062)

This will allow removing the dependency of the compositor on
`script_traits`, which should make our internal dependency chain a lot
easier to deal with.

Part of #35984.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/constellation/tracing.rs

@@ -86,6 +86,7 @@ mod from_compositor {
                 Self::ExitFullScreen(_) => target!("ExitFullScreen"),
                 Self::MediaSessionAction(_) => target!("MediaSessionAction"),
                 Self::SetWebViewThrottled(_, _) => target!("SetWebViewThrottled"),
+                Self::SetScrollStates(..) => target!("SetScrollStates"),
             }
         }
     }