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diff --git a/gfx/wr/webrender_api/src/lib.rs b/gfx/wr/webrender_api/src/lib.rs
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+/* 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 http://mozilla.org/MPL/2.0/. */
+
+//! The `webrender_api` crate contains an assortment types and functions used
+//! by WebRender consumers as well as, in many cases, WebRender itself.
+//!
+//! This separation allows Servo to parallelize compilation across `webrender`
+//! and other crates that depend on `webrender_api`. So in practice, we put
+//! things in this crate when Servo needs to use them. Firefox depends on the
+//! `webrender` crate directly, and so this distinction is not really relevant
+//! there.
+
+#![cfg_attr(feature = "nightly", feature(nonzero))]
+#![cfg_attr(feature = "cargo-clippy", allow(clippy::float_cmp, clippy::too_many_arguments))]
+#![cfg_attr(feature = "cargo-clippy", allow(clippy::unreadable_literal, clippy::new_without_default))]
+
+pub extern crate crossbeam_channel;
+pub extern crate euclid;
+
+extern crate app_units;
+#[macro_use]
+extern crate bitflags;
+extern crate byteorder;
+#[cfg(feature = "nightly")]
+extern crate core;
+#[cfg(target_os = "macos")]
+extern crate core_foundation;
+#[cfg(target_os = "macos")]
+extern crate core_graphics;
+extern crate derive_more;
+#[macro_use]
+extern crate malloc_size_of_derive;
+extern crate serde;
+#[macro_use]
+extern crate serde_derive;
+extern crate time;
+
+extern crate malloc_size_of;
+extern crate peek_poke;
+
+pub mod channel;
+mod color;
+mod display_item;
+mod display_item_cache;
+mod display_list;
+mod font;
+mod gradient_builder;
+mod image;
+pub mod units;
+
+pub use crate::color::*;
+pub use crate::display_item::*;
+pub use crate::display_item_cache::DisplayItemCache;
+pub use crate::display_list::*;
+pub use crate::font::*;
+pub use crate::gradient_builder::*;
+pub use crate::image::*;
+
+use crate::units::*;
+use crate::channel::Receiver;
+use std::marker::PhantomData;
+use std::sync::Arc;
+use std::os::raw::c_void;
+use peek_poke::PeekPoke;
+
+/// Width and height in device pixels of image tiles.
+pub type TileSize = u16;
+
+/// Various settings that the caller can select based on desired tradeoffs
+/// between rendering quality and performance / power usage.
+#[derive(Copy, Clone, Deserialize, Serialize)]
+pub struct QualitySettings {
+    /// If true, disable creating separate picture cache slices when the
+    /// scroll root changes. This gives maximum opportunity to find an
+    /// opaque background, which enables subpixel AA. However, it is
+    /// usually significantly more expensive to render when scrolling.
+    pub force_subpixel_aa_where_possible: bool,
+}
+
+impl Default for QualitySettings {
+    fn default() -> Self {
+        QualitySettings {
+            // Prefer performance over maximum subpixel AA quality, since WR
+            // already enables subpixel AA in more situations than other browsers.
+            force_subpixel_aa_where_possible: false,
+        }
+    }
+}
+
+/// An epoch identifies the state of a pipeline in time.
+///
+/// This is mostly used as a synchronization mechanism to observe how/when particular pipeline
+/// updates propagate through WebRender and are applied at various stages.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, Ord, PartialEq, PartialOrd, Serialize)]
+pub struct Epoch(pub u32);
+
+impl Epoch {
+    /// Magic invalid epoch value.
+    pub fn invalid() -> Epoch {
+        Epoch(u32::MAX)
+    }
+}
+
+/// ID namespaces uniquely identify different users of WebRender's API.
+///
+/// For example in Gecko each content process uses a separate id namespace.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default, Eq, MallocSizeOf, PartialEq, Hash, Ord, PartialOrd, PeekPoke)]
+#[derive(Deserialize, Serialize)]
+pub struct IdNamespace(pub u32);
+
+/// A key uniquely identifying a WebRender document.
+///
+/// Instances can manage one or several documents (using the same render backend thread).
+/// Each document will internally correspond to a single scene, and scenes are made of
+/// one or several pipelines.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize, PeekPoke)]
+pub struct DocumentId {
+    ///
+    pub namespace_id: IdNamespace,
+    ///
+    pub id: u32,
+}
+
+impl DocumentId {
+    ///
+    pub fn new(namespace_id: IdNamespace, id: u32) -> Self {
+        DocumentId {
+            namespace_id,
+            id,
+        }
+    }
+
+    ///
+    pub const INVALID: DocumentId = DocumentId { namespace_id: IdNamespace(0), id: 0 };
+}
+
+/// This type carries no valuable semantics for WR. However, it reflects the fact that
+/// clients (Servo) may generate pipelines by different semi-independent sources.
+/// These pipelines still belong to the same `IdNamespace` and the same `DocumentId`.
+/// Having this extra Id field enables them to generate `PipelineId` without collision.
+pub type PipelineSourceId = u32;
+
+/// From the point of view of WR, `PipelineId` is completely opaque and generic as long as
+/// it's clonable, serializable, comparable, and hashable.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize, PeekPoke)]
+pub struct PipelineId(pub PipelineSourceId, pub u32);
+
+impl Default for PipelineId {
+    fn default() -> Self {
+        PipelineId::dummy()
+    }
+}
+
+impl PipelineId {
+    ///
+    pub fn dummy() -> Self {
+        PipelineId(0, 0)
+    }
+}
+
+
+/// An opaque pointer-sized value.
+#[repr(C)]
+#[derive(Clone)]
+pub struct ExternalEvent {
+    raw: usize,
+}
+
+unsafe impl Send for ExternalEvent {}
+
+impl ExternalEvent {
+    /// Creates the event from an opaque pointer-sized value.
+    pub fn from_raw(raw: usize) -> Self {
+        ExternalEvent { raw }
+    }
+    /// Consumes self to make it obvious that the event should be forwarded only once.
+    pub fn unwrap(self) -> usize {
+        self.raw
+    }
+}
+
+/// Describe whether or not scrolling should be clamped by the content bounds.
+#[derive(Clone, Deserialize, Serialize)]
+pub enum ScrollClamping {
+    ///
+    ToContentBounds,
+    ///
+    NoClamping,
+}
+
+/// A handler to integrate WebRender with the thread that contains the `Renderer`.
+pub trait RenderNotifier: Send {
+    ///
+    fn clone(&self) -> Box<dyn RenderNotifier>;
+    /// Wake the thread containing the `Renderer` up (after updates have been put
+    /// in the renderer's queue).
+    fn wake_up(
+        &self,
+        composite_needed: bool,
+    );
+    /// Notify the thread containing the `Renderer` that a new frame is ready.
+    fn new_frame_ready(&self, _: DocumentId, scrolled: bool, composite_needed: bool, render_time_ns: Option<u64>);
+    /// A Gecko-specific notification mechanism to get some code executed on the
+    /// `Renderer`'s thread, mostly replaced by `NotificationHandler`. You should
+    /// probably use the latter instead.
+    fn external_event(&self, _evt: ExternalEvent) {
+        unimplemented!()
+    }
+    /// Notify the thread containing the `Renderer` that the render backend has been
+    /// shut down.
+    fn shut_down(&self) {}
+}
+
+/// A stage of the rendering pipeline.
+#[repr(u32)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum Checkpoint {
+    ///
+    SceneBuilt,
+    ///
+    FrameBuilt,
+    ///
+    FrameTexturesUpdated,
+    ///
+    FrameRendered,
+    /// NotificationRequests get notified with this if they get dropped without having been
+    /// notified. This provides the guarantee that if a request is created it will get notified.
+    TransactionDropped,
+}
+
+/// A handler to notify when a transaction reaches certain stages of the rendering
+/// pipeline.
+pub trait NotificationHandler : Send + Sync {
+    /// Entry point of the handler to implement. Invoked by WebRender.
+    fn notify(&self, when: Checkpoint);
+}
+
+/// A request to notify a handler when the transaction reaches certain stages of the
+/// rendering pipeline.
+///
+/// The request is guaranteed to be notified once and only once, even if the transaction
+/// is dropped before the requested check-point.
+pub struct NotificationRequest {
+    handler: Option<Box<dyn NotificationHandler>>,
+    when: Checkpoint,
+}
+
+impl NotificationRequest {
+    /// Constructor.
+    pub fn new(when: Checkpoint, handler: Box<dyn NotificationHandler>) -> Self {
+        NotificationRequest {
+            handler: Some(handler),
+            when,
+        }
+    }
+
+    /// The specified stage at which point the handler should be notified.
+    pub fn when(&self) -> Checkpoint { self.when }
+
+    /// Called by WebRender at specified stages to notify the registered handler.
+    pub fn notify(mut self) {
+        if let Some(handler) = self.handler.take() {
+            handler.notify(self.when);
+        }
+    }
+}
+
+/// An object that can perform hit-testing without doing synchronous queries to
+/// the RenderBackendThread.
+pub trait ApiHitTester: Send + Sync {
+    /// Does a hit test on display items in the specified document, at the given
+    /// point. If a pipeline_id is specified, it is used to further restrict the
+    /// hit results so that only items inside that pipeline are matched. The vector
+    /// of hit results will contain all display items that match, ordered from
+    /// front to back.
+    fn hit_test(&self, pipeline_id: Option<PipelineId>, point: WorldPoint) -> HitTestResult;
+}
+
+/// A hit tester requested to the render backend thread but not necessarily ready yet.
+///
+/// The request should be resolved as late as possible to reduce the likelihood of blocking.
+pub struct HitTesterRequest {
+    #[doc(hidden)]
+    pub rx: Receiver<Arc<dyn ApiHitTester>>,
+}
+
+impl HitTesterRequest {
+    /// Block until the hit tester is available and return it, consuming teh request.
+    pub fn resolve(self) -> Arc<dyn ApiHitTester> {
+        self.rx.recv().unwrap()
+    }
+}
+
+/// Describe an item that matched a hit-test query.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct HitTestItem {
+    /// The pipeline that the display item that was hit belongs to.
+    pub pipeline: PipelineId,
+
+    /// The tag of the hit display item.
+    pub tag: ItemTag,
+
+    /// The hit point in the coordinate space of the "viewport" of the display item. The
+    /// viewport is the scroll node formed by the root reference frame of the display item's
+    /// pipeline.
+    pub point_in_viewport: LayoutPoint,
+
+    /// The coordinates of the original hit test point relative to the origin of this item.
+    /// This is useful for calculating things like text offsets in the client.
+    pub point_relative_to_item: LayoutPoint,
+}
+
+/// Returned by `RenderApi::hit_test`.
+#[derive(Clone, Debug, Default, Deserialize, Serialize)]
+pub struct HitTestResult {
+    /// List of items that are match the hit-test query.
+    pub items: Vec<HitTestItem>,
+}
+
+impl Drop for NotificationRequest {
+    fn drop(&mut self) {
+        if let Some(ref mut handler) = self.handler {
+            handler.notify(Checkpoint::TransactionDropped);
+        }
+    }
+}
+
+// This Clone impl yields an "empty" request because we don't want the requests
+// to be notified twice so the request is owned by only one of the API messages
+// (the original one) after the clone.
+// This works in practice because the notifications requests are used for
+// synchronization so we don't need to include them in the recording mechanism
+// in wrench that clones the messages.
+impl Clone for NotificationRequest {
+    fn clone(&self) -> Self {
+        NotificationRequest {
+            when: self.when,
+            handler: None,
+        }
+    }
+}
+
+
+/// A key to identify an animated property binding.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default, Deserialize, MallocSizeOf, PartialEq, Serialize, Eq, Hash, PeekPoke)]
+pub struct PropertyBindingId {
+    pub namespace: IdNamespace,
+    pub uid: u32,
+}
+
+impl PropertyBindingId {
+    /// Constructor.
+    pub fn new(value: u64) -> Self {
+        PropertyBindingId {
+            namespace: IdNamespace((value >> 32) as u32),
+            uid: value as u32,
+        }
+    }
+}
+
+/// A unique key that is used for connecting animated property
+/// values to bindings in the display list.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize, PeekPoke)]
+pub struct PropertyBindingKey<T> {
+    ///
+    pub id: PropertyBindingId,
+    #[doc(hidden)]
+    pub _phantom: PhantomData<T>,
+}
+
+/// Construct a property value from a given key and value.
+impl<T: Copy> PropertyBindingKey<T> {
+    ///
+    pub fn with(self, value: T) -> PropertyValue<T> {
+        PropertyValue { key: self, value }
+    }
+}
+
+impl<T> PropertyBindingKey<T> {
+    /// Constructor.
+    pub fn new(value: u64) -> Self {
+        PropertyBindingKey {
+            id: PropertyBindingId::new(value),
+            _phantom: PhantomData,
+        }
+    }
+}
+
+/// A binding property can either be a specific value
+/// (the normal, non-animated case) or point to a binding location
+/// to fetch the current value from.
+/// Note that Binding has also a non-animated value, the value is
+/// used for the case where the animation is still in-delay phase
+/// (i.e. the animation doesn't produce any animation values).
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize, PeekPoke)]
+pub enum PropertyBinding<T> {
+    /// Non-animated value.
+    Value(T),
+    /// Animated binding.
+    Binding(PropertyBindingKey<T>, T),
+}
+
+impl<T: Default> Default for PropertyBinding<T> {
+    fn default() -> Self {
+        PropertyBinding::Value(Default::default())
+    }
+}
+
+impl<T> From<T> for PropertyBinding<T> {
+    fn from(value: T) -> PropertyBinding<T> {
+        PropertyBinding::Value(value)
+    }
+}
+
+impl From<PropertyBindingKey<ColorF>> for PropertyBindingKey<ColorU> {
+    fn from(key: PropertyBindingKey<ColorF>) -> PropertyBindingKey<ColorU> {
+        PropertyBindingKey {
+            id: key.id.clone(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
+impl From<PropertyBindingKey<ColorU>> for PropertyBindingKey<ColorF> {
+    fn from(key: PropertyBindingKey<ColorU>) -> PropertyBindingKey<ColorF> {
+        PropertyBindingKey {
+            id: key.id.clone(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
+impl From<PropertyBinding<ColorF>> for PropertyBinding<ColorU> {
+    fn from(value: PropertyBinding<ColorF>) -> PropertyBinding<ColorU> {
+        match value {
+            PropertyBinding::Value(value) => PropertyBinding::Value(value.into()),
+            PropertyBinding::Binding(k, v) => {
+                PropertyBinding::Binding(k.into(), v.into())
+            }
+        }
+    }
+}
+
+impl From<PropertyBinding<ColorU>> for PropertyBinding<ColorF> {
+    fn from(value: PropertyBinding<ColorU>) -> PropertyBinding<ColorF> {
+        match value {
+            PropertyBinding::Value(value) => PropertyBinding::Value(value.into()),
+            PropertyBinding::Binding(k, v) => {
+                PropertyBinding::Binding(k.into(), v.into())
+            }
+        }
+    }
+}
+
+/// The current value of an animated property. This is
+/// supplied by the calling code.
+#[derive(Clone, Copy, Debug, Deserialize, Serialize, PartialEq)]
+pub struct PropertyValue<T> {
+    ///
+    pub key: PropertyBindingKey<T>,
+    ///
+    pub value: T,
+}
+
+/// When using `generate_frame()`, a list of `PropertyValue` structures
+/// can optionally be supplied to provide the current value of any
+/// animated properties.
+#[derive(Clone, Deserialize, Serialize, Debug, PartialEq, Default)]
+pub struct DynamicProperties {
+    ///
+    pub transforms: Vec<PropertyValue<LayoutTransform>>,
+    /// opacity
+    pub floats: Vec<PropertyValue<f32>>,
+    /// background color
+    pub colors: Vec<PropertyValue<ColorF>>,
+}
+
+/// A C function that takes a pointer to a heap allocation and returns its size.
+///
+/// This is borrowed from the malloc_size_of crate, upon which we want to avoid
+/// a dependency from WebRender.
+pub type VoidPtrToSizeFn = unsafe extern "C" fn(ptr: *const c_void) -> usize;
+
+bitflags! {
+    /// Flags to enable/disable various builtin debugging tools.
+    #[repr(C)]
+    #[derive(Default, Deserialize, MallocSizeOf, Serialize)]
+    pub struct DebugFlags: u32 {
+        /// Display the frame profiler on screen.
+        const PROFILER_DBG          = 1 << 0;
+        /// Display intermediate render targets on screen.
+        const RENDER_TARGET_DBG     = 1 << 1;
+        /// Display all texture cache pages on screen.
+        const TEXTURE_CACHE_DBG     = 1 << 2;
+        /// Display GPU timing results.
+        const GPU_TIME_QUERIES      = 1 << 3;
+        /// Query the number of pixels that pass the depth test divided and show it
+        /// in the profiler as a percentage of the number of pixels in the screen
+        /// (window width times height).
+        const GPU_SAMPLE_QUERIES    = 1 << 4;
+        /// Render each quad with their own draw call.
+        ///
+        /// Terrible for performance but can help with understanding the drawing
+        /// order when inspecting renderdoc or apitrace recordings.
+        const DISABLE_BATCHING      = 1 << 5;
+        /// Display the pipeline epochs.
+        const EPOCHS                = 1 << 6;
+        /// Print driver messages to stdout.
+        const ECHO_DRIVER_MESSAGES  = 1 << 7;
+        /// Show an overlay displaying overdraw amount.
+        const SHOW_OVERDRAW         = 1 << 8;
+        /// Display the contents of GPU cache.
+        const GPU_CACHE_DBG         = 1 << 9;
+        /// Clear evicted parts of the texture cache for debugging purposes.
+        const TEXTURE_CACHE_DBG_CLEAR_EVICTED = 1 << 10;
+        /// Show picture caching debug overlay
+        const PICTURE_CACHING_DBG   = 1 << 11;
+        /// Highlight all primitives with colors based on kind.
+        const PRIMITIVE_DBG = 1 << 12;
+        /// Draw a zoom widget showing part of the framebuffer zoomed in.
+        const ZOOM_DBG = 1 << 13;
+        /// Scale the debug renderer down for a smaller screen. This will disrupt
+        /// any mapping between debug display items and page content, so shouldn't
+        /// be used with overlays like the picture caching or primitive display.
+        const SMALL_SCREEN = 1 << 14;
+        /// Disable various bits of the WebRender pipeline, to help narrow
+        /// down where slowness might be coming from.
+        const DISABLE_OPAQUE_PASS = 1 << 15;
+        ///
+        const DISABLE_ALPHA_PASS = 1 << 16;
+        ///
+        const DISABLE_CLIP_MASKS = 1 << 17;
+        ///
+        const DISABLE_TEXT_PRIMS = 1 << 18;
+        ///
+        const DISABLE_GRADIENT_PRIMS = 1 << 19;
+        ///
+        const OBSCURE_IMAGES = 1 << 20;
+        /// Taint the transparent area of the glyphs with a random opacity to easily
+        /// see when glyphs are re-rasterized.
+        const GLYPH_FLASHING = 1 << 21;
+        /// The profiler only displays information that is out of the ordinary.
+        const SMART_PROFILER        = 1 << 22;
+        /// If set, dump picture cache invalidation debug to console.
+        const INVALIDATION_DBG = 1 << 23;
+        /// Log tile cache to memory for later saving as part of wr-capture
+        const TILE_CACHE_LOGGING_DBG   = 1 << 24;
+        /// Collect and dump profiler statistics to captures.
+        const PROFILER_CAPTURE = (1 as u32) << 25; // need "as u32" until we have cbindgen#556
+        /// Invalidate picture tiles every frames (useful when inspecting GPU work in external tools).
+        const FORCE_PICTURE_INVALIDATION = (1 as u32) << 26;
+    }
+}
+
+/// Information specific to a primitive type that
+/// uniquely identifies a primitive template by key.
+#[derive(Debug, Clone, Eq, MallocSizeOf, PartialEq, Hash, Serialize, Deserialize)]
+pub enum PrimitiveKeyKind {
+    /// Clear an existing rect, used for special effects on some platforms.
+    Clear,
+    ///
+    Rectangle {
+        ///
+        color: PropertyBinding<ColorU>,
+    },
+}
+
+///
+#[derive(Clone)]
+pub struct ScrollNodeState {
+    ///
+    pub id: ExternalScrollId,
+    ///
+    pub scroll_offset: LayoutVector2D,
+}
+
+///
+#[derive(Clone, Copy, Debug)]
+pub enum ScrollLocation {
+    /// Scroll by a certain amount.
+    Delta(LayoutVector2D),
+    /// Scroll to very top of element.
+    Start,
+    /// Scroll to very bottom of element.
+    End,
+}
+
+/// Represents a zoom factor.
+#[derive(Clone, Copy, Debug)]
+pub struct ZoomFactor(f32);
+
+impl ZoomFactor {
+    /// Construct a new zoom factor.
+    pub fn new(scale: f32) -> Self {
+        ZoomFactor(scale)
+    }
+
+    /// Get the zoom factor as an untyped float.
+    pub fn get(self) -> f32 {
+        self.0
+    }
+}
+
+/// Crash annotations included in crash reports.
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub enum CrashAnnotation {
+    CompileShader = 0,
+}
+
+/// Handler to expose support for annotating crash reports.
+pub trait CrashAnnotator : Send {
+    fn set(&self, annotation: CrashAnnotation, value: &str);
+    fn clear(&self, annotation: CrashAnnotation);
+    fn box_clone(&self) -> Box<dyn CrashAnnotator>;
+}
+
+impl Clone for Box<dyn CrashAnnotator> {
+    fn clone(&self) -> Box<dyn CrashAnnotator> {
+        self.box_clone()
+    }
+}
+
+/// Guard to add a crash annotation at creation, and clear it at destruction.
+pub struct CrashAnnotatorGuard<'a> {
+    annotator: &'a Option<Box<dyn CrashAnnotator>>,
+    annotation: CrashAnnotation,
+}
+
+impl<'a> CrashAnnotatorGuard<'a> {
+    pub fn new(annotator: &'a Option<Box<dyn CrashAnnotator>>, annotation: CrashAnnotation, value: &str) -> Self {
+        if let Some(ref annotator) = annotator {
+            annotator.set(annotation, value);
+        }
+        Self {
+            annotator,
+            annotation,
+        }
+    }
+}
+
+impl<'a> Drop for CrashAnnotatorGuard<'a> {
+    fn drop(&mut self) {
+        if let Some(ref annotator) = self.annotator {
+            annotator.clear(self.annotation);
+        }
+    }
+}