Create a constellation_traits crate (#36088)

This change creates a `constellation_traits` crate. Previously messages
to the `Constellation` were in the `compositing_traits` crate, which
came about organically. This change moves these to a new crate which
also contains data types that are used in both compositing/libservo and
script (ie types that cross the process boundary). The idea is similar
to `embedding_traits`, but this is meant for types not exposed to the
API.

This change allows deduplicating `UntrustedNodeAddress`, which
previously had two versions to avoid circular dependencies.

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

components/shared/base/id.rs

@@ -16,7 +16,7 @@ use malloc_size_of::malloc_size_of_is_0;
 use malloc_size_of_derive::MallocSizeOf;
 use parking_lot::Mutex;
 use serde::{Deserialize, Serialize};
-use webrender_api::{ExternalScrollId, PipelineId as WebRenderPipelineId};
+use webrender_api::{ExternalScrollId, PipelineId as WebRenderPipelineId, SpatialId};
 
 /// Asserts the size of a type at compile time.
 macro_rules! size_of_test {
@@ -442,3 +442,15 @@ pub const TEST_BROWSING_CONTEXT_ID: BrowsingContextId = BrowsingContextId {
 };
 
 pub const TEST_WEBVIEW_ID: WebViewId = WebViewId(TEST_BROWSING_CONTEXT_ID);
+
+/// An id for a ScrollTreeNode in the ScrollTree. This contains both the index
+/// to the node in the tree's array of nodes as well as the corresponding SpatialId
+/// for the SpatialNode in the WebRender display list.
+#[derive(Clone, Copy, Debug, Default, Deserialize, PartialEq, Serialize)]
+pub struct ScrollTreeNodeId {
+    /// The index of this scroll tree node in the tree's array of nodes.
+    pub index: usize,
+
+    /// The WebRender spatial id of this scroll tree node.
+    pub spatial_id: SpatialId,
+}

components/shared/compositing/Cargo.toml

@@ -17,11 +17,9 @@ crossbeam-channel = { workspace = true }
 embedder_traits = { workspace = true }
 euclid = { workspace = true }
 ipc-channel = { workspace = true }
-keyboard-types = { workspace = true }
 log = { workspace = true }
 pixels = { path = '../../pixels' }
 script_traits = { workspace = true }
-servo_url = { path = "../../url" }
 strum_macros = { workspace = true }
 stylo_traits = { workspace = true }
 webrender_api = { workspace = true }

components/shared/compositing/lib.rs

@@ -2,14 +2,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
-//! Communication with the compositor thread.
-
-mod constellation_msg;
+//! The interface to the `compositing` crate.
 
 use std::fmt::{Debug, Error, Formatter};
 
 use base::id::{PipelineId, WebViewId};
-pub use constellation_msg::{ConstellationMsg, PaintMetricEvent};
 use crossbeam_channel::{Receiver, Sender};
 use embedder_traits::{EventLoopWaker, MouseButton, MouseButtonAction};
 use euclid::Rect;

components/shared/constellation/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "constellation_traits"
+version.workspace = true
+authors.workspace = true
+license.workspace = true
+edition.workspace = true
+publish.workspace = true
+rust-version.workspace = true
+
+[lib]
+name = "constellation_traits"
+path = "lib.rs"
+
+[dependencies]
+base = { workspace = true }
+bitflags = { workspace = true }
+embedder_traits = { workspace = true }
+euclid = { workspace = true }
+ipc-channel = { workspace = true }
+malloc_size_of = { workspace = true }
+malloc_size_of_derive = { workspace = true }
+serde = { workspace = true }
+servo_url = { path = "../../url" }
+strum_macros = { workspace = true }
+stylo_traits = { workspace = true }
+webrender_api = { workspace = true }

components/shared/constellation/lib.rs

@@ -0,0 +1,224 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! The interface to the `Constellation`, which prevents other crates from depending directly on
+//! the `constellation` crate itself. In addition to all messages to the `Constellation`, this
+//! crate is responsible for defining types that cross the process boundary from the
+//! embedding/rendering layer all the way to script, thus it should have very minimal dependencies
+//! on other parts of Servo.
+
+use std::collections::HashMap;
+use std::ffi::c_void;
+use std::fmt;
+use std::time::Duration;
+
+use base::Epoch;
+use base::cross_process_instant::CrossProcessInstant;
+use base::id::{PipelineId, ScrollTreeNodeId, WebViewId};
+use bitflags::bitflags;
+use embedder_traits::{Cursor, InputEvent, MediaSessionActionType, Theme, WebDriverCommandMsg};
+use euclid::{Scale, Size2D, Vector2D};
+use ipc_channel::ipc::IpcSender;
+use malloc_size_of::malloc_size_of_is_0;
+use malloc_size_of_derive::MallocSizeOf;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use servo_url::ServoUrl;
+use strum_macros::IntoStaticStr;
+use style_traits::CSSPixel;
+use webrender_api::ExternalScrollId;
+use webrender_api::units::{DevicePixel, LayoutPixel};
+
+/// Messages to the constellation.
+#[derive(IntoStaticStr)]
+pub enum ConstellationMsg {
+    /// Exit the constellation.
+    Exit,
+    /// Request that the constellation send the current focused top-level browsing context id,
+    /// over a provided channel.
+    GetFocusTopLevelBrowsingContext(IpcSender<Option<WebViewId>>),
+    /// Query the constellation to see if the current compositor output is stable
+    IsReadyToSaveImage(HashMap<PipelineId, Epoch>),
+    /// Whether to allow script to navigate.
+    AllowNavigationResponse(PipelineId, bool),
+    /// Request to load a page.
+    LoadUrl(WebViewId, ServoUrl),
+    /// Clear the network cache.
+    ClearCache,
+    /// Request to traverse the joint session history of the provided browsing context.
+    TraverseHistory(WebViewId, TraversalDirection),
+    /// Inform the constellation of a window being resized.
+    WindowSize(WebViewId, WindowSizeData, WindowSizeType),
+    /// Inform the constellation of a theme change.
+    ThemeChange(Theme),
+    /// Requests that the constellation instruct layout to begin a new tick of the animation.
+    TickAnimation(PipelineId, AnimationTickType),
+    /// Dispatch a webdriver command
+    WebDriverCommand(WebDriverCommandMsg),
+    /// Reload a top-level browsing context.
+    Reload(WebViewId),
+    /// A log entry, with the top-level browsing context id and thread name
+    LogEntry(Option<WebViewId>, Option<String>, LogEntry),
+    /// Create a new top level browsing context.
+    NewWebView(ServoUrl, WebViewId),
+    /// Close a top level browsing context.
+    CloseWebView(WebViewId),
+    /// Panic a top level browsing context.
+    SendError(Option<WebViewId>, String),
+    /// Make a webview focused.
+    FocusWebView(WebViewId),
+    /// Make none of the webviews focused.
+    BlurWebView,
+    /// Forward an input event to an appropriate ScriptTask.
+    ForwardInputEvent(WebViewId, InputEvent, Option<CompositorHitTestResult>),
+    /// Requesting a change to the onscreen cursor.
+    SetCursor(WebViewId, Cursor),
+    /// Enable the sampling profiler, with a given sampling rate and max total sampling duration.
+    ToggleProfiler(Duration, Duration),
+    /// Request to exit from fullscreen mode
+    ExitFullScreen(WebViewId),
+    /// Media session action.
+    MediaSessionAction(MediaSessionActionType),
+    /// Set whether to use less resources, by stopping animations and running timers at a heavily limited rate.
+    SetWebViewThrottled(WebViewId, bool),
+    /// The Servo renderer scrolled and is updating the scroll states of the nodes in the
+    /// given pipeline via the constellation.
+    SetScrollStates(PipelineId, Vec<ScrollState>),
+    /// Notify the constellation that a particular paint metric event has happened for the given pipeline.
+    PaintMetric(PipelineId, PaintMetricEvent),
+}
+
+/// A description of a paint metric that is sent from the Servo renderer to the
+/// constellation.
+pub enum PaintMetricEvent {
+    FirstPaint(CrossProcessInstant, bool /* first_reflow */),
+    FirstContentfulPaint(CrossProcessInstant, bool /* first_reflow */),
+}
+
+impl fmt::Debug for ConstellationMsg {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        let variant_string: &'static str = self.into();
+        write!(formatter, "ConstellationMsg::{variant_string}")
+    }
+}
+
+/// A log entry reported to the constellation
+/// We don't report all log entries, just serious ones.
+/// We need a separate type for this because `LogLevel` isn't serializable.
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub enum LogEntry {
+    /// Panic, with a reason and backtrace
+    Panic(String, String),
+    /// Error, with a reason
+    Error(String),
+    /// warning, with a reason
+    Warn(String),
+}
+
+/// Data about the window size.
+#[derive(Clone, Copy, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
+pub struct WindowSizeData {
+    /// The size of the initial layout viewport, before parsing an
+    /// <http://www.w3.org/TR/css-device-adapt/#initial-viewport>
+    pub initial_viewport: Size2D<f32, CSSPixel>,
+
+    /// The resolution of the window in dppx, not including any "pinch zoom" factor.
+    pub device_pixel_ratio: Scale<f32, CSSPixel, DevicePixel>,
+}
+
+/// The type of window size change.
+#[derive(Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
+pub enum WindowSizeType {
+    /// Initial load.
+    Initial,
+    /// Window resize.
+    Resize,
+}
+
+bitflags! {
+    #[derive(Debug, Default, Deserialize, Serialize)]
+    /// Specifies if rAF should be triggered and/or CSS Animations and Transitions.
+    pub struct AnimationTickType: u8 {
+        /// Trigger a call to requestAnimationFrame.
+        const REQUEST_ANIMATION_FRAME = 0b001;
+        /// Trigger restyles for CSS Animations and Transitions.
+        const CSS_ANIMATIONS_AND_TRANSITIONS = 0b010;
+    }
+}
+
+/// The result of a hit test in the compositor.
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub struct CompositorHitTestResult {
+    /// The pipeline id of the resulting item.
+    pub pipeline_id: PipelineId,
+
+    /// The hit test point in the item's viewport.
+    pub point_in_viewport: euclid::default::Point2D<f32>,
+
+    /// The hit test point relative to the item itself.
+    pub point_relative_to_item: euclid::default::Point2D<f32>,
+
+    /// The node address of the hit test result.
+    pub node: UntrustedNodeAddress,
+
+    /// The cursor that should be used when hovering the item hit by the hit test.
+    pub cursor: Option<Cursor>,
+
+    /// The scroll tree node associated with this hit test item.
+    pub scroll_tree_node: ScrollTreeNodeId,
+}
+
+/// The scroll state of a stacking context.
+#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
+pub struct ScrollState {
+    /// The ID of the scroll root.
+    pub scroll_id: ExternalScrollId,
+    /// The scrolling offset of this stacking context.
+    pub scroll_offset: Vector2D<f32, LayoutPixel>,
+}
+
+/// The address of a node. Layout sends these back. They must be validated via
+/// `from_untrusted_node_address` before they can be used, because we do not trust layout.
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct UntrustedNodeAddress(pub *const c_void);
+
+malloc_size_of_is_0!(UntrustedNodeAddress);
+
+#[allow(unsafe_code)]
+unsafe impl Send for UntrustedNodeAddress {}
+
+impl From<style_traits::dom::OpaqueNode> for UntrustedNodeAddress {
+    fn from(o: style_traits::dom::OpaqueNode) -> Self {
+        UntrustedNodeAddress(o.0 as *const c_void)
+    }
+}
+
+impl Serialize for UntrustedNodeAddress {
+    fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
+        (self.0 as usize).serialize(s)
+    }
+}
+
+impl<'de> Deserialize<'de> for UntrustedNodeAddress {
+    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<UntrustedNodeAddress, D::Error> {
+        let value: usize = Deserialize::deserialize(d)?;
+        Ok(UntrustedNodeAddress::from_id(value))
+    }
+}
+
+impl UntrustedNodeAddress {
+    /// Creates an `UntrustedNodeAddress` from the given pointer address value.
+    #[inline]
+    pub fn from_id(id: usize) -> UntrustedNodeAddress {
+        UntrustedNodeAddress(id as *const c_void)
+    }
+}
+
+/// The direction of a history traversal
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
+pub enum TraversalDirection {
+    /// Travel forward the given number of documents.
+    Forward(usize),
+    /// Travel backward the given number of documents.
+    Back(usize),
+}

components/shared/embedder/lib.rs

@@ -2,6 +2,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+//! Types used by the embedding layer and/or exposed to the API. This crate is responsible for
+//! defining types that cross the process boundary from the embedding/rendering layer all the way
+//! to script, thus it should have very minimal dependencies on other parts of Servo. If a type
+//! is not exposed in the API or doesn't involve messages sent to the embedding/libservo layer, it
+//! is probably a better fit for the `constellation_traits` crate.
+
 pub mod input_events;
 pub mod resources;
 mod webdriver;
@@ -526,15 +532,6 @@ impl WebResourceResponse {
     }
 }
 
-/// The direction of a history traversal
-#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
-pub enum TraversalDirection {
-    /// Travel forward the given number of documents.
-    Forward(usize),
-    /// Travel backward the given number of documents.
-    Back(usize),
-}
-
 /// The type of platform theme.
 #[derive(Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
 pub enum Theme {

components/shared/script/Cargo.toml

@@ -21,6 +21,7 @@ base = { workspace = true }
 bitflags = { workspace = true }
 bluetooth_traits = { workspace = true, optional = true }
 canvas_traits = { workspace = true }
+constellation_traits = { workspace = true }
 cookie = { workspace = true }
 crossbeam-channel = { workspace = true }
 devtools_traits = { workspace = true }

components/shared/script/lib.rs

@@ -24,10 +24,12 @@ use base::id::{
     BlobId, BrowsingContextId, HistoryStateId, MessagePortId, PipelineId, PipelineNamespaceId,
     WebViewId,
 };
-use bitflags::bitflags;
 #[cfg(feature = "bluetooth")]
 use bluetooth_traits::BluetoothRequest;
 use canvas_traits::webgl::WebGLPipeline;
+use constellation_traits::{
+    AnimationTickType, CompositorHitTestResult, ScrollState, WindowSizeData, WindowSizeType,
+};
 use crossbeam_channel::{RecvTimeoutError, Sender};
 use devtools_traits::{DevtoolScriptControlMsg, ScriptToDevtoolsControlMsg, WorkerId};
 use embedder_traits::input_events::InputEvent;
@@ -36,9 +38,7 @@ use euclid::{Rect, Scale, Size2D, UnknownUnit};
 use http::{HeaderMap, Method};
 use ipc_channel::Error as IpcError;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
-use libc::c_void;
 use log::warn;
-use malloc_size_of::malloc_size_of_is_0;
 use malloc_size_of_derive::MallocSizeOf;
 use media::WindowGLContext;
 use net_traits::image_cache::ImageCache;
@@ -47,7 +47,7 @@ use net_traits::storage_thread::StorageType;
 use net_traits::{ReferrerPolicy, ResourceThreads};
 use pixels::PixelFormat;
 use profile_traits::{mem, time as profile_time};
-use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use serde::{Deserialize, Serialize};
 use servo_url::{ImmutableOrigin, ServoUrl};
 use strum::{EnumIter, IntoEnumIterator};
 use strum_macros::IntoStaticStr;
@@ -57,61 +57,15 @@ use stylo_atoms::Atom;
 use webgpu::WebGPUMsg;
 use webrender_api::units::DevicePixel;
 use webrender_api::{DocumentId, ImageKey};
-use webrender_traits::{
-    CompositorHitTestResult, CrossProcessCompositorApi, ScrollState,
-    UntrustedNodeAddress as WebRenderUntrustedNodeAddress,
-};
+use webrender_traits::CrossProcessCompositorApi;
 
 pub use crate::script_msg::{
-    DOMMessage, IFrameSizeMsg, Job, JobError, JobResult, JobResultValue, JobType, LogEntry,
-    SWManagerMsg, SWManagerSenders, ScopeThings, ScriptMsg, ServiceWorkerMsg, TouchEventResult,
+    DOMMessage, IFrameSizeMsg, Job, JobError, JobResult, JobResultValue, JobType, SWManagerMsg,
+    SWManagerSenders, ScopeThings, ScriptMsg, ServiceWorkerMsg, TouchEventResult,
 };
 use crate::serializable::BlobImpl;
 use crate::transferable::MessagePortImpl;
 
-/// The address of a node. Layout sends these back. They must be validated via
-/// `from_untrusted_node_address` before they can be used, because we do not trust layout.
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-pub struct UntrustedNodeAddress(pub *const c_void);
-
-malloc_size_of_is_0!(UntrustedNodeAddress);
-
-#[allow(unsafe_code)]
-unsafe impl Send for UntrustedNodeAddress {}
-
-impl From<WebRenderUntrustedNodeAddress> for UntrustedNodeAddress {
-    fn from(o: WebRenderUntrustedNodeAddress) -> Self {
-        UntrustedNodeAddress(o.0)
-    }
-}
-
-impl From<style_traits::dom::OpaqueNode> for UntrustedNodeAddress {
-    fn from(o: style_traits::dom::OpaqueNode) -> Self {
-        UntrustedNodeAddress(o.0 as *const c_void)
-    }
-}
-
-impl Serialize for UntrustedNodeAddress {
-    fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
-        (self.0 as usize).serialize(s)
-    }
-}
-
-impl<'de> Deserialize<'de> for UntrustedNodeAddress {
-    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<UntrustedNodeAddress, D::Error> {
-        let value: usize = Deserialize::deserialize(d)?;
-        Ok(UntrustedNodeAddress::from_id(value))
-    }
-}
-
-impl UntrustedNodeAddress {
-    /// Creates an `UntrustedNodeAddress` from the given pointer address value.
-    #[inline]
-    pub fn from_id(id: usize) -> UntrustedNodeAddress {
-        UntrustedNodeAddress(id as *const c_void)
-    }
-}
-
 /// The origin where a given load was initiated.
 /// Useful for origin checks, for example before evaluation a JS URL.
 #[derive(Clone, Debug, Deserialize, Serialize)]
@@ -581,37 +535,6 @@ pub struct IFrameLoadInfoWithData {
     pub window_size: WindowSizeData,
 }
 
-bitflags! {
-    #[derive(Debug, Default, Deserialize, Serialize)]
-    /// Specifies if rAF should be triggered and/or CSS Animations and Transitions.
-    pub struct AnimationTickType: u8 {
-        /// Trigger a call to requestAnimationFrame.
-        const REQUEST_ANIMATION_FRAME = 0b001;
-        /// Trigger restyles for CSS Animations and Transitions.
-        const CSS_ANIMATIONS_AND_TRANSITIONS = 0b010;
-    }
-}
-
-/// Data about the window size.
-#[derive(Clone, Copy, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
-pub struct WindowSizeData {
-    /// The size of the initial layout viewport, before parsing an
-    /// <http://www.w3.org/TR/css-device-adapt/#initial-viewport>
-    pub initial_viewport: Size2D<f32, CSSPixel>,
-
-    /// The resolution of the window in dppx, not including any "pinch zoom" factor.
-    pub device_pixel_ratio: Scale<f32, CSSPixel, DevicePixel>,
-}
-
-/// The type of window size change.
-#[derive(Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
-pub enum WindowSizeType {
-    /// Initial load.
-    Initial,
-    /// Window resize.
-    Resize,
-}
-
 /// Resources required by workerglobalscopes
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct WorkerGlobalScopeInit {

components/shared/script/script_msg.rs

@@ -11,10 +11,9 @@ use base::id::{
     MessagePortRouterId, PipelineId, ServiceWorkerId, ServiceWorkerRegistrationId, WebViewId,
 };
 use canvas_traits::canvas::{CanvasId, CanvasMsg};
+use constellation_traits::{LogEntry, TraversalDirection};
 use devtools_traits::{ScriptToDevtoolsControlMsg, WorkerId};
-use embedder_traits::{
-    EmbedderMsg, MediaSessionEvent, TouchEventType, TouchSequenceId, TraversalDirection,
-};
+use embedder_traits::{EmbedderMsg, MediaSessionEvent, TouchEventType, TouchSequenceId};
 use euclid::Size2D;
 use euclid::default::Size2D as UntypedSize2D;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
@@ -55,19 +54,6 @@ pub enum TouchEventResult {
     DefaultPrevented(TouchSequenceId, TouchEventType),
 }
 
-/// A log entry reported to the constellation
-/// We don't report all log entries, just serious ones.
-/// We need a separate type for this because `LogLevel` isn't serializable.
-#[derive(Clone, Debug, Deserialize, Serialize)]
-pub enum LogEntry {
-    /// Panic, with a reason and backtrace
-    Panic(String, String),
-    /// Error, with a reason
-    Error(String),
-    /// warning, with a reason
-    Warn(String),
-}
-
 /// Messages from the script to the constellation.
 #[derive(Deserialize, IntoStaticStr, Serialize)]
 pub enum ScriptMsg {

components/shared/script/tests/compositor.rs

@@ -2,11 +2,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use base::id::ScrollTreeNodeId;
 use euclid::Size2D;
 use webrender_api::units::LayoutVector2D;
 use webrender_api::{ExternalScrollId, PipelineId, ScrollLocation, SpatialId};
 use webrender_traits::display_list::{
-    AxesScrollSensitivity, ScrollSensitivity, ScrollTree, ScrollTreeNodeId, ScrollableNodeInfo,
+    AxesScrollSensitivity, ScrollSensitivity, ScrollTree, ScrollableNodeInfo,
 };
 
 fn add_mock_scroll_node(tree: &mut ScrollTree) -> ScrollTreeNodeId {

components/shared/script_layout/Cargo.toml

@@ -16,6 +16,7 @@ base = { workspace = true }
 app_units = { workspace = true }
 atomic_refcell = { workspace = true }
 canvas_traits = { workspace = true }
+constellation_traits = { workspace = true }
 euclid = { workspace = true }
 fnv = { workspace = true }
 fonts = { path = "../../fonts" }

components/shared/script_layout/lib.rs

@@ -20,6 +20,7 @@ use atomic_refcell::AtomicRefCell;
 use base::Epoch;
 use base::id::{BrowsingContextId, PipelineId, WebViewId};
 use canvas_traits::canvas::{CanvasId, CanvasMsg};
+use constellation_traits::{ScrollState, UntrustedNodeAddress, WindowSizeData};
 use euclid::Size2D;
 use euclid::default::{Point2D, Rect};
 use fnv::FnvHashMap;
@@ -30,10 +31,7 @@ use malloc_size_of_derive::MallocSizeOf;
 use net_traits::image_cache::{ImageCache, PendingImageId};
 use profile_traits::mem::Report;
 use profile_traits::time;
-use script_traits::{
-    InitialScriptState, LoadData, Painter, ScriptThreadMessage, UntrustedNodeAddress,
-    WindowSizeData,
-};
+use script_traits::{InitialScriptState, LoadData, Painter, ScriptThreadMessage};
 use serde::{Deserialize, Serialize};
 use servo_arc::Arc as ServoArc;
 use servo_url::{ImmutableOrigin, ServoUrl};
@@ -51,7 +49,7 @@ use style::selector_parser::{PseudoElement, RestyleDamage, Snapshot};
 use style::stylesheets::Stylesheet;
 use style_traits::CSSPixel;
 use webrender_api::ImageKey;
-use webrender_traits::{CrossProcessCompositorApi, ScrollState};
+use webrender_traits::CrossProcessCompositorApi;
 
 pub type GenericLayoutData = dyn Any + Send + Sync;
 

components/shared/webrender/Cargo.toml

@@ -17,6 +17,7 @@ no-wgl = ["surfman/sm-angle-default"]
 
 [dependencies]
 base = { workspace = true }
+constellation_traits = { workspace = true }
 embedder_traits = { workspace = true }
 euclid = { workspace = true }
 image = { workspace = true }

components/shared/webrender/display_list.rs

@@ -4,6 +4,7 @@
 
 //! Defines data structures which are consumed by the Compositor.
 
+use base::id::ScrollTreeNodeId;
 use embedder_traits::Cursor;
 use serde::{Deserialize, Serialize};
 use style::values::specified::Overflow;
@@ -54,18 +55,6 @@ pub struct HitTestInfo {
     pub scroll_tree_node: ScrollTreeNodeId,
 }
 
-/// An id for a ScrollTreeNode in the ScrollTree. This contains both the index
-/// to the node in the tree's array of nodes as well as the corresponding SpatialId
-/// for the SpatialNode in the WebRender display list.
-#[derive(Clone, Copy, Debug, Default, Deserialize, PartialEq, Serialize)]
-pub struct ScrollTreeNodeId {
-    /// The index of this scroll tree node in the tree's array of nodes.
-    pub index: usize,
-
-    /// The WebRender spatial id of this scroll tree node.
-    pub spatial_id: SpatialId,
-}
-
 /// Data stored for nodes in the [ScrollTree] that actually scroll,
 /// as opposed to reference frames and sticky nodes which do not.
 #[derive(Debug, Deserialize, Serialize)]

components/shared/webrender/lib.rs

@@ -11,17 +11,15 @@ use core::fmt;
 use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
 
-use base::id::{PipelineId, WebViewId};
-use display_list::{CompositorDisplayListInfo, ScrollTreeNodeId};
-use embedder_traits::Cursor;
-use euclid::Vector2D;
+use base::id::WebViewId;
+use constellation_traits::CompositorHitTestResult;
+use display_list::CompositorDisplayListInfo;
 use euclid::default::Size2D as UntypedSize2D;
 use ipc_channel::ipc::{self, IpcSender, IpcSharedMemory};
-use libc::c_void;
 use log::warn;
-use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use serde::{Deserialize, Serialize};
 use servo_geometry::{DeviceIndependentIntRect, DeviceIndependentIntSize};
-use webrender_api::units::{DevicePoint, LayoutPixel, LayoutPoint, TexelRect};
+use webrender_api::units::{DevicePoint, LayoutPoint, TexelRect};
 use webrender_api::{
     BuiltDisplayList, BuiltDisplayListDescriptor, ExternalImage, ExternalImageData,
     ExternalImageHandler, ExternalImageId, ExternalImageSource, ExternalScrollId,
@@ -480,63 +478,3 @@ impl From<SerializableImageData> for ImageData {
         }
     }
 }
-
-/// The address of a node. Layout sends these back. They must be validated via
-/// `from_untrusted_node_address` before they can be used, because we do not trust layout.
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-pub struct UntrustedNodeAddress(pub *const c_void);
-
-#[allow(unsafe_code)]
-unsafe impl Send for UntrustedNodeAddress {}
-
-impl Serialize for UntrustedNodeAddress {
-    fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
-        (self.0 as usize).serialize(s)
-    }
-}
-
-impl<'de> Deserialize<'de> for UntrustedNodeAddress {
-    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<UntrustedNodeAddress, D::Error> {
-        let value: usize = Deserialize::deserialize(d)?;
-        Ok(UntrustedNodeAddress::from_id(value))
-    }
-}
-
-impl UntrustedNodeAddress {
-    /// Creates an `UntrustedNodeAddress` from the given pointer address value.
-    #[inline]
-    pub fn from_id(id: usize) -> UntrustedNodeAddress {
-        UntrustedNodeAddress(id as *const c_void)
-    }
-}
-
-/// The result of a hit test in the compositor.
-#[derive(Clone, Debug, Deserialize, Serialize)]
-pub struct CompositorHitTestResult {
-    /// The pipeline id of the resulting item.
-    pub pipeline_id: PipelineId,
-
-    /// The hit test point in the item's viewport.
-    pub point_in_viewport: euclid::default::Point2D<f32>,
-
-    /// The hit test point relative to the item itself.
-    pub point_relative_to_item: euclid::default::Point2D<f32>,
-
-    /// The node address of the hit test result.
-    pub node: UntrustedNodeAddress,
-
-    /// The cursor that should be used when hovering the item hit by the hit test.
-    pub cursor: Option<Cursor>,
-
-    /// The scroll tree node associated with this hit test item.
-    pub scroll_tree_node: ScrollTreeNodeId,
-}
-
-/// The scroll state of a stacking context.
-#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
-pub struct ScrollState {
-    /// The ID of the scroll root.
-    pub scroll_id: ExternalScrollId,
-    /// The scrolling offset of this stacking context.
-    pub scroll_offset: Vector2D<f32, LayoutPixel>,
-}