script_layout: Remove script to layout messages (#32081)

Instead of communicating with layout via messages, script can simply
call methods on the layout trait. This simplifies the way that script
communicates with layout and opens the path to sharing more data
structures between the two systems. This is part of a continuing 
series of cleanups after removing the layout thread.

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- [x] These changes do not require tests because they should not change
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2 files changed, 164 insertions, 196 deletions

diff --git a/components/shared/script_layout/lib.rs b/components/shared/script_layout/lib.rs
index b36c0c4ef56..e6d91ee86a0 100644
--- a/components/shared/script_layout/lib.rs
+++ b/components/shared/script_layout/lib.rs
@@ -8,7 +8,6 @@
 
 #![deny(unsafe_code)]
 
-pub mod message;
 pub mod wrapper_traits;
 
 use std::any::Any;
@@ -19,6 +18,7 @@ use std::sync::Arc;
 use app_units::Au;
 use atomic_refcell::AtomicRefCell;
 use canvas_traits::canvas::{CanvasId, CanvasMsg};
+use crossbeam_channel::Sender;
 use euclid::default::{Point2D, Rect};
 use euclid::Size2D;
 use gfx::font_cache_thread::FontCacheThread;
@@ -26,25 +26,28 @@ use gfx_traits::Epoch;
 use ipc_channel::ipc::IpcSender;
 use libc::c_void;
 use malloc_size_of_derive::MallocSizeOf;
-use message::NodesFromPointQueryType;
 use metrics::PaintTimeMetrics;
 use msg::constellation_msg::{BrowsingContextId, PipelineId};
 use net_traits::image_cache::{ImageCache, PendingImageId};
+use profile_traits::mem::ReportsChan;
 use profile_traits::time;
 use script_traits::{
-    ConstellationControlMsg, InitialScriptState, LayoutControlMsg, LayoutMsg, LoadData,
-    UntrustedNodeAddress, WebrenderIpcSender, WindowSizeData,
+    ConstellationControlMsg, InitialScriptState, LayoutControlMsg, LayoutMsg, LoadData, Painter,
+    ScrollState, UntrustedNodeAddress, WebrenderIpcSender, WindowSizeData,
 };
 use servo_arc::Arc as ServoArc;
 use servo_url::{ImmutableOrigin, ServoUrl};
 use style::animation::DocumentAnimationSet;
+use style::context::QuirksMode;
 use style::data::ElementData;
 use style::dom::OpaqueNode;
+use style::invalidation::element::restyle_hints::RestyleHint;
 use style::media_queries::Device;
 use style::properties::style_structs::Font;
 use style::properties::PropertyId;
-use style::selector_parser::PseudoElement;
+use style::selector_parser::{PseudoElement, RestyleDamage, Snapshot};
 use style::stylesheets::Stylesheet;
+use style::Atom;
 use style_traits::CSSPixel;
 use webrender_api::ImageKey;
 
@@ -171,9 +174,6 @@ pub trait LayoutFactory: Send + Sync {
 }
 
 pub trait Layout {
-    /// Process a single message from script.
-    fn process(&mut self, msg: message::Msg);
-
     /// Handle a single message from the Constellation.
     fn handle_constellation_msg(&mut self, msg: LayoutControlMsg);
 
@@ -203,9 +203,30 @@ pub trait Layout {
         before_stylsheet: Option<ServoArc<Stylesheet>>,
     );
 
+    /// Inform the layout that its ScriptThread is about to exit.
+    fn exit_now(&mut self);
+
+    /// Requests that layout measure its memory usage. The resulting reports are sent back
+    /// via the supplied channel.
+    fn collect_reports(&self, reports_chan: ReportsChan);
+
+    /// Sets quirks mode for the document, causing the quirks mode stylesheet to be used.
+    fn set_quirks_mode(&mut self, quirks_mode: QuirksMode);
+
     /// Removes a stylesheet from the Layout.
     fn remove_stylesheet(&mut self, stylesheet: ServoArc<Stylesheet>);
 
+    /// Requests a reflow.
+    fn reflow(&mut self, script_reflow: ScriptReflow);
+
+    /// Tells layout that script has added some paint worklet modules.
+    fn register_paint_worklet_modules(
+        &mut self,
+        name: Atom,
+        properties: Vec<Atom>,
+        painter: Box<dyn Painter>,
+    );
+
     fn query_content_box(&self, node: OpaqueNode) -> Option<Rect<Au>>;
     fn query_content_boxes(&self, node: OpaqueNode) -> Vec<Rect<Au>>;
     fn query_client_rect(&self, node: OpaqueNode) -> Rect<i32>;
@@ -257,3 +278,138 @@ pub struct OffsetParentResponse {
     pub node_address: Option<UntrustedNodeAddress>,
     pub rect: Rect<Au>,
 }
+
+#[derive(Debug, PartialEq)]
+pub enum NodesFromPointQueryType {
+    All,
+    Topmost,
+}
+
+#[derive(Debug, PartialEq)]
+pub enum QueryMsg {
+    ContentBox,
+    ContentBoxes,
+    ClientRectQuery,
+    ScrollingAreaQuery,
+    OffsetParentQuery,
+    TextIndexQuery,
+    NodesFromPointQuery,
+    ResolvedStyleQuery,
+    StyleQuery,
+    ElementInnerTextQuery,
+    ResolvedFontStyleQuery,
+    InnerWindowDimensionsQuery,
+}
+
+/// Any query to perform with this reflow.
+#[derive(Debug, PartialEq)]
+pub enum ReflowGoal {
+    Full,
+    TickAnimations,
+    LayoutQuery(QueryMsg, u64),
+
+    /// Tells layout about a single new scrolling offset from the script. The rest will
+    /// remain untouched and layout won't forward this back to script.
+    UpdateScrollNode(ScrollState),
+}
+
+impl ReflowGoal {
+    /// Returns true if the given ReflowQuery needs a full, up-to-date display list to
+    /// be present or false if it only needs stacking-relative positions.
+    pub fn needs_display_list(&self) -> bool {
+        match *self {
+            ReflowGoal::Full | ReflowGoal::TickAnimations | ReflowGoal::UpdateScrollNode(_) => true,
+            ReflowGoal::LayoutQuery(ref querymsg, _) => match *querymsg {
+                QueryMsg::ElementInnerTextQuery |
+                QueryMsg::InnerWindowDimensionsQuery |
+                QueryMsg::NodesFromPointQuery |
+                QueryMsg::ResolvedStyleQuery |
+                QueryMsg::TextIndexQuery => true,
+                QueryMsg::ClientRectQuery |
+                QueryMsg::ContentBox |
+                QueryMsg::ContentBoxes |
+                QueryMsg::OffsetParentQuery |
+                QueryMsg::ResolvedFontStyleQuery |
+                QueryMsg::ScrollingAreaQuery |
+                QueryMsg::StyleQuery => false,
+            },
+        }
+    }
+
+    /// Returns true if the given ReflowQuery needs its display list send to WebRender or
+    /// false if a layout_thread display list is sufficient.
+    pub fn needs_display(&self) -> bool {
+        match *self {
+            ReflowGoal::Full | ReflowGoal::TickAnimations | ReflowGoal::UpdateScrollNode(_) => true,
+            ReflowGoal::LayoutQuery(ref querymsg, _) => match *querymsg {
+                QueryMsg::NodesFromPointQuery |
+                QueryMsg::TextIndexQuery |
+                QueryMsg::ElementInnerTextQuery => true,
+                QueryMsg::ContentBox |
+                QueryMsg::ContentBoxes |
+                QueryMsg::ClientRectQuery |
+                QueryMsg::ScrollingAreaQuery |
+                QueryMsg::ResolvedStyleQuery |
+                QueryMsg::ResolvedFontStyleQuery |
+                QueryMsg::OffsetParentQuery |
+                QueryMsg::InnerWindowDimensionsQuery |
+                QueryMsg::StyleQuery => false,
+            },
+        }
+    }
+}
+
+/// Information needed for a reflow.
+pub struct Reflow {
+    ///  A clipping rectangle for the page, an enlarged rectangle containing the viewport.
+    pub page_clip_rect: Rect<Au>,
+}
+
+/// Information derived from a layout pass that needs to be returned to the script thread.
+#[derive(Default)]
+pub struct ReflowComplete {
+    /// The list of images that were encountered that are in progress.
+    pub pending_images: Vec<PendingImage>,
+}
+
+/// Information needed for a script-initiated reflow.
+pub struct ScriptReflow {
+    /// General reflow data.
+    pub reflow_info: Reflow,
+    /// The document node.
+    pub document: TrustedNodeAddress,
+    /// The dirty root from which to restyle.
+    pub dirty_root: Option<TrustedNodeAddress>,
+    /// Whether the document's stylesheets have changed since the last script reflow.
+    pub stylesheets_changed: bool,
+    /// The current window size.
+    pub window_size: WindowSizeData,
+    /// The channel that we send a notification to.
+    pub script_join_chan: Sender<ReflowComplete>,
+    /// The goal of this reflow.
+    pub reflow_goal: ReflowGoal,
+    /// The number of objects in the dom #10110
+    pub dom_count: u32,
+    /// The current window origin
+    pub origin: ImmutableOrigin,
+    /// Restyle snapshot map.
+    pub pending_restyles: Vec<(TrustedNodeAddress, PendingRestyle)>,
+    /// The current animation timeline value.
+    pub animation_timeline_value: f64,
+    /// The set of animations for this document.
+    pub animations: DocumentAnimationSet,
+}
+
+/// A pending restyle.
+#[derive(Debug, Default, MallocSizeOf)]
+pub struct PendingRestyle {
+    /// If this element had a state or attribute change since the last restyle, track
+    /// the original condition of the element.
+    pub snapshot: Option<Snapshot>,
+
+    /// Any explicit restyles hints that have been accumulated for this element.
+    pub hint: RestyleHint,
+
+    /// Any explicit restyles damage that have been accumulated for this element.
+    pub damage: RestyleDamage,
+}
diff --git a/components/shared/script_layout/message.rs b/components/shared/script_layout/message.rs
deleted file mode 100644
index 018e554e893..00000000000
--- a/components/shared/script_layout/message.rs
+++ /dev/null
@@ -1,188 +0,0 @@
-/* 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/. */
-
-use app_units::Au;
-use crossbeam_channel::Sender;
-use euclid::default::Rect;
-use malloc_size_of_derive::MallocSizeOf;
-use profile_traits::mem::ReportsChan;
-use script_traits::{Painter, ScrollState, WindowSizeData};
-use servo_atoms::Atom;
-use servo_url::ImmutableOrigin;
-use style::animation::DocumentAnimationSet;
-use style::context::QuirksMode;
-use style::invalidation::element::restyle_hints::RestyleHint;
-use style::selector_parser::{RestyleDamage, Snapshot};
-
-use crate::{PendingImage, TrustedNodeAddress};
-
-/// Asynchronous messages that script can send to layout.
-pub enum Msg {
-    /// Change the quirks mode.
-    SetQuirksMode(QuirksMode),
-
-    /// Requests a reflow.
-    Reflow(ScriptReflow),
-
-    /// Requests that layout measure its memory usage. The resulting reports are sent back
-    /// via the supplied channel.
-    CollectReports(ReportsChan),
-
-    /// Requests that layout immediately shut down. There must be no more nodes left after
-    /// this, or layout will crash.
-    ExitNow,
-
-    /// Tells layout about the new scrolling offsets of each scrollable stacking context.
-    SetScrollStates(Vec<ScrollState>),
-
-    /// Tells layout that script has added some paint worklet modules.
-    RegisterPaint(Atom, Vec<Atom>, Box<dyn Painter>),
-}
-
-#[derive(Debug, PartialEq)]
-pub enum NodesFromPointQueryType {
-    All,
-    Topmost,
-}
-
-#[derive(Debug, PartialEq)]
-pub enum QueryMsg {
-    ContentBox,
-    ContentBoxes,
-    ClientRectQuery,
-    ScrollingAreaQuery,
-    OffsetParentQuery,
-    TextIndexQuery,
-    NodesFromPointQuery,
-    ResolvedStyleQuery,
-    StyleQuery,
-    ElementInnerTextQuery,
-    ResolvedFontStyleQuery,
-    InnerWindowDimensionsQuery,
-}
-
-/// Any query to perform with this reflow.
-#[derive(Debug, PartialEq)]
-pub enum ReflowGoal {
-    Full,
-    TickAnimations,
-    LayoutQuery(QueryMsg, u64),
-
-    /// Tells layout about a single new scrolling offset from the script. The rest will
-    /// remain untouched and layout won't forward this back to script.
-    UpdateScrollNode(ScrollState),
-}
-
-impl ReflowGoal {
-    /// Returns true if the given ReflowQuery needs a full, up-to-date display list to
-    /// be present or false if it only needs stacking-relative positions.
-    pub fn needs_display_list(&self) -> bool {
-        match *self {
-            ReflowGoal::Full | ReflowGoal::TickAnimations | ReflowGoal::UpdateScrollNode(_) => true,
-            ReflowGoal::LayoutQuery(ref querymsg, _) => match *querymsg {
-                QueryMsg::ElementInnerTextQuery |
-                QueryMsg::InnerWindowDimensionsQuery |
-                QueryMsg::NodesFromPointQuery |
-                QueryMsg::ResolvedStyleQuery |
-                QueryMsg::TextIndexQuery => true,
-                QueryMsg::ClientRectQuery |
-                QueryMsg::ContentBox |
-                QueryMsg::ContentBoxes |
-                QueryMsg::OffsetParentQuery |
-                QueryMsg::ResolvedFontStyleQuery |
-                QueryMsg::ScrollingAreaQuery |
-                QueryMsg::StyleQuery => false,
-            },
-        }
-    }
-
-    /// Returns true if the given ReflowQuery needs its display list send to WebRender or
-    /// false if a layout_thread display list is sufficient.
-    pub fn needs_display(&self) -> bool {
-        match *self {
-            ReflowGoal::Full | ReflowGoal::TickAnimations | ReflowGoal::UpdateScrollNode(_) => true,
-            ReflowGoal::LayoutQuery(ref querymsg, _) => match *querymsg {
-                QueryMsg::NodesFromPointQuery |
-                QueryMsg::TextIndexQuery |
-                QueryMsg::ElementInnerTextQuery => true,
-                QueryMsg::ContentBox |
-                QueryMsg::ContentBoxes |
-                QueryMsg::ClientRectQuery |
-                QueryMsg::ScrollingAreaQuery |
-                QueryMsg::ResolvedStyleQuery |
-                QueryMsg::ResolvedFontStyleQuery |
-                QueryMsg::OffsetParentQuery |
-                QueryMsg::InnerWindowDimensionsQuery |
-                QueryMsg::StyleQuery => false,
-            },
-        }
-    }
-}
-
-/// Information needed for a reflow.
-pub struct Reflow {
-    ///  A clipping rectangle for the page, an enlarged rectangle containing the viewport.
-    pub page_clip_rect: Rect<Au>,
-}
-
-/// Information derived from a layout pass that needs to be returned to the script thread.
-#[derive(Default)]
-pub struct ReflowComplete {
-    /// The list of images that were encountered that are in progress.
-    pub pending_images: Vec<PendingImage>,
-}
-
-/// Information needed for a script-initiated reflow.
-pub struct ScriptReflow {
-    /// General reflow data.
-    pub reflow_info: Reflow,
-    /// The document node.
-    pub document: TrustedNodeAddress,
-    /// The dirty root from which to restyle.
-    pub dirty_root: Option<TrustedNodeAddress>,
-    /// Whether the document's stylesheets have changed since the last script reflow.
-    pub stylesheets_changed: bool,
-    /// The current window size.
-    pub window_size: WindowSizeData,
-    /// The channel that we send a notification to.
-    pub script_join_chan: Sender<ReflowComplete>,
-    /// The goal of this reflow.
-    pub reflow_goal: ReflowGoal,
-    /// The number of objects in the dom #10110
-    pub dom_count: u32,
-    /// The current window origin
-    pub origin: ImmutableOrigin,
-    /// Restyle snapshot map.
-    pub pending_restyles: Vec<(TrustedNodeAddress, PendingRestyle)>,
-    /// The current animation timeline value.
-    pub animation_timeline_value: f64,
-    /// The set of animations for this document.
-    pub animations: DocumentAnimationSet,
-}
-
-/// A pending restyle.
-#[derive(Debug, MallocSizeOf)]
-pub struct PendingRestyle {
-    /// If this element had a state or attribute change since the last restyle, track
-    /// the original condition of the element.
-    pub snapshot: Option<Snapshot>,
-
-    /// Any explicit restyles hints that have been accumulated for this element.
-    pub hint: RestyleHint,
-
-    /// Any explicit restyles damage that have been accumulated for this element.
-    pub damage: RestyleDamage,
-}
-
-impl Default for PendingRestyle {
-    /// Creates a new empty pending restyle.
-    #[inline]
-    fn default() -> Self {
-        Self {
-            snapshot: None,
-            hint: RestyleHint::empty(),
-            damage: RestyleDamage::empty(),
-        }
-    }
-}