libservo: Move WebDriver messages to the embedder crate (#35602)

This is the first step toward moving the WebDriver implementation to
servoshell. This move will make it possible to start testing the
embedding API with WebDriver. See [this zulip thread][a] for more details.

While WebDriver will be able to use a lot of API commands to do what it
is doing now, there will still need to be some "cheat codes" for more
gnarly access to `ScriptThread` details. That's why we likely won't be
able to remove all WebDriver-specific messages from the API -- but maybe
they will be useful for embedders somehow.

A couple messages have to change as they depended on `script_traits`
types, particularly those that used `WindowSizeData` and `LoadData`. I
think this helps to encapsulate the WebDriver commands a bit more
though.

[a]: https://servo.zulipchat.com/#narrow/channel/437943-embedding/topic/webdriver.20as.20embedding.20api.20playgound

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

components/shared/compositing/constellation_msg.rs

@@ -8,11 +8,11 @@ use std::time::Duration;
 
 use base::id::{BrowsingContextId, PipelineId, TopLevelBrowsingContextId, WebViewId};
 use base::Epoch;
-use embedder_traits::{Cursor, InputEvent, MediaSessionActionType, Theme, TraversalDirection};
-use ipc_channel::ipc::IpcSender;
-use script_traits::{
-    AnimationTickType, LogEntry, WebDriverCommandMsg, WindowSizeData, WindowSizeType,
+use embedder_traits::{
+    Cursor, InputEvent, MediaSessionActionType, Theme, TraversalDirection, WebDriverCommandMsg,
 };
+use ipc_channel::ipc::IpcSender;
+use script_traits::{AnimationTickType, LogEntry, WindowSizeData, WindowSizeType};
 use servo_url::ServoUrl;
 use webrender_traits::CompositorHitTestResult;
 

components/shared/embedder/Cargo.toml

@@ -17,6 +17,7 @@ webxr = ["dep:webxr-api"]
 [dependencies]
 base = { workspace = true }
 cfg-if = { workspace = true }
+cookie = { workspace = true }
 crossbeam-channel = { workspace = true }
 euclid = { workspace = true }
 http = { workspace = true }
@@ -28,8 +29,11 @@ num-derive = "0.4"
 malloc_size_of = { workspace = true }
 malloc_size_of_derive = { workspace = true }
 num-traits = { workspace = true }
+pixels = { path = "../../pixels" }
 serde = { workspace = true }
 servo_url = { path = "../../url" }
+style_traits = { workspace = true }
 url = { workspace = true }
+webdriver = { workspace = true }
 webrender_api = { workspace = true }
 webxr-api = { workspace = true, features = ["ipc"], optional = true }

components/shared/embedder/lib.rs

@@ -4,6 +4,7 @@
 
 pub mod input_events;
 pub mod resources;
+mod webdriver;
 
 use std::fmt::{Debug, Error, Formatter};
 use std::path::PathBuf;
@@ -22,6 +23,7 @@ use url::Url;
 use webrender_api::units::{DeviceIntPoint, DeviceIntRect, DeviceIntSize};
 
 pub use crate::input_events::*;
+pub use crate::webdriver::*;
 
 /// Tracks whether Servo isn't shutting down, is in the process of shutting down,
 /// or has finished shutting down.

components/shared/embedder/webdriver.rs

@@ -6,15 +6,66 @@
 
 use std::collections::HashMap;
 
-use base::id::BrowsingContextId;
+use base::id::{BrowsingContextId, WebViewId};
 use cookie::Cookie;
-use euclid::default::Rect;
+use euclid::default::Rect as UntypedRect;
+use euclid::{Rect, Size2D};
 use hyper_serde::Serde;
 use ipc_channel::ipc::IpcSender;
+use keyboard_types::webdriver::Event as WebDriverInputEvent;
+use keyboard_types::KeyboardEvent;
+use pixels::Image;
 use serde::{Deserialize, Serialize};
 use servo_url::ServoUrl;
+use style_traits::CSSPixel;
 use webdriver::common::{WebElement, WebFrame, WebWindow};
 use webdriver::error::ErrorStatus;
+use webrender_api::units::DeviceIntSize;
+
+use crate::{MouseButton, MouseButtonAction};
+
+/// Messages to the constellation originating from the WebDriver server.
+#[derive(Debug, Deserialize, Serialize)]
+pub enum WebDriverCommandMsg {
+    /// Get the window size.
+    GetWindowSize(WebViewId, IpcSender<Size2D<f32, CSSPixel>>),
+    /// Load a URL in the top-level browsing context with the given ID.
+    LoadUrl(WebViewId, ServoUrl, IpcSender<WebDriverLoadStatus>),
+    /// Refresh the top-level browsing context with the given ID.
+    Refresh(WebViewId, IpcSender<WebDriverLoadStatus>),
+    /// Pass a webdriver command to the script thread of the current pipeline
+    /// of a browsing context.
+    ScriptCommand(BrowsingContextId, WebDriverScriptCommand),
+    /// Act as if keys were pressed in the browsing context with the given ID.
+    SendKeys(BrowsingContextId, Vec<WebDriverInputEvent>),
+    /// Act as if keys were pressed or release in the browsing context with the given ID.
+    KeyboardAction(BrowsingContextId, KeyboardEvent),
+    /// Act as if the mouse was clicked in the browsing context with the given ID.
+    MouseButtonAction(MouseButtonAction, MouseButton, f32, f32),
+    /// Act as if the mouse was moved in the browsing context with the given ID.
+    MouseMoveAction(f32, f32),
+    /// Set the window size.
+    SetWindowSize(WebViewId, DeviceIntSize, IpcSender<Size2D<f32, CSSPixel>>),
+    /// Take a screenshot of the window.
+    TakeScreenshot(
+        WebViewId,
+        Option<Rect<f32, CSSPixel>>,
+        IpcSender<Option<Image>>,
+    ),
+    /// Create a new webview that loads about:blank. The constellation will use
+    /// the provided channels to return the top level browsing context id
+    /// associated with the new webview, and a notification when the initial
+    /// load is complete.
+    NewWebView(
+        WebViewId,
+        IpcSender<WebViewId>,
+        IpcSender<WebDriverLoadStatus>,
+    ),
+    /// Close the webview associated with the provided id.
+    CloseWebView(WebViewId),
+    /// Focus the webview associated with the provided id.
+    FocusWebView(WebViewId),
+}
 
 #[derive(Debug, Deserialize, Serialize)]
 pub enum WebDriverScriptCommand {
@@ -75,11 +126,11 @@ pub enum WebDriverScriptCommand {
         IpcSender<Result<WebDriverJSValue, ErrorStatus>>,
     ),
     GetElementCSS(String, String, IpcSender<Result<String, ErrorStatus>>),
-    GetElementRect(String, IpcSender<Result<Rect<f64>, ErrorStatus>>),
+    GetElementRect(String, IpcSender<Result<UntypedRect<f64>, ErrorStatus>>),
     GetElementTagName(String, IpcSender<Result<String, ErrorStatus>>),
     GetElementText(String, IpcSender<Result<String, ErrorStatus>>),
     GetElementInViewCenterPoint(String, IpcSender<Result<Option<(i64, i64)>, ErrorStatus>>),
-    GetBoundingClientRect(String, IpcSender<Result<Rect<f32>, ErrorStatus>>),
+    GetBoundingClientRect(String, IpcSender<Result<UntypedRect<f32>, ErrorStatus>>),
     GetBrowsingContextId(
         WebDriverFrameId,
         IpcSender<Result<BrowsingContextId, ErrorStatus>>,
@@ -133,8 +184,8 @@ pub enum WebDriverFrameId {
 }
 
 #[derive(Debug, Deserialize, Serialize)]
-pub enum LoadStatus {
-    LoadComplete,
-    LoadTimeout,
-    LoadCanceled,
+pub enum WebDriverLoadStatus {
+    Complete,
+    Timeout,
+    Canceled,
 }

components/shared/script/lib.rs

@@ -12,7 +12,6 @@
 mod script_msg;
 pub mod serializable;
 pub mod transferable;
-pub mod webdriver_msg;
 
 use std::borrow::Cow;
 use std::collections::{HashMap, VecDeque};
@@ -23,7 +22,7 @@ use background_hang_monitor_api::BackgroundHangMonitorRegister;
 use base::cross_process_instant::CrossProcessInstant;
 use base::id::{
     BlobId, BrowsingContextId, HistoryStateId, MessagePortId, PipelineId, PipelineNamespaceId,
-    TopLevelBrowsingContextId, WebViewId,
+    TopLevelBrowsingContextId,
 };
 use base::Epoch;
 use bitflags::bitflags;
@@ -33,13 +32,11 @@ use canvas_traits::webgl::WebGLPipeline;
 use crossbeam_channel::{RecvTimeoutError, Sender};
 use devtools_traits::{DevtoolScriptControlMsg, ScriptToDevtoolsControlMsg, WorkerId};
 use embedder_traits::input_events::InputEvent;
-use embedder_traits::{MediaSessionActionType, MouseButton, MouseButtonAction, Theme};
+use embedder_traits::{MediaSessionActionType, Theme, WebDriverScriptCommand};
 use euclid::{Rect, Scale, Size2D, UnknownUnit, Vector2D};
 use http::{HeaderMap, Method};
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use ipc_channel::Error as IpcError;
-use keyboard_types::webdriver::Event as WebDriverInputEvent;
-use keyboard_types::KeyboardEvent;
 use libc::c_void;
 use log::warn;
 use malloc_size_of::malloc_size_of_is_0;
@@ -49,7 +46,7 @@ use net_traits::image_cache::ImageCache;
 use net_traits::request::{InsecureRequestsPolicy, Referrer, RequestBody};
 use net_traits::storage_thread::StorageType;
 use net_traits::{ReferrerPolicy, ResourceThreads};
-use pixels::{Image, PixelFormat};
+use pixels::PixelFormat;
 use profile_traits::{mem, time as profile_time};
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use servo_atoms::Atom;
@@ -57,7 +54,7 @@ use servo_url::{ImmutableOrigin, ServoUrl};
 use style_traits::{CSSPixel, SpeculativePainter};
 #[cfg(feature = "webgpu")]
 use webgpu::WebGPUMsg;
-use webrender_api::units::{DeviceIntSize, DevicePixel, LayoutPixel};
+use webrender_api::units::{DevicePixel, LayoutPixel};
 use webrender_api::{DocumentId, ExternalScrollId, ImageKey};
 use webrender_traits::{
     CompositorHitTestResult, CrossProcessCompositorApi,
@@ -70,7 +67,6 @@ pub use crate::script_msg::{
 };
 use crate::serializable::{BlobData, BlobImpl};
 use crate::transferable::MessagePortImpl;
-use crate::webdriver_msg::{LoadStatus, WebDriverScriptCommand};
 
 /// 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.
@@ -652,53 +648,6 @@ pub enum WindowSizeType {
     Resize,
 }
 
-/// Messages to the constellation originating from the WebDriver server.
-#[derive(Debug, Deserialize, Serialize)]
-pub enum WebDriverCommandMsg {
-    /// Get the window size.
-    GetWindowSize(TopLevelBrowsingContextId, IpcSender<WindowSizeData>),
-    /// Load a URL in the top-level browsing context with the given ID.
-    LoadUrl(TopLevelBrowsingContextId, LoadData, IpcSender<LoadStatus>),
-    /// Refresh the top-level browsing context with the given ID.
-    Refresh(TopLevelBrowsingContextId, IpcSender<LoadStatus>),
-    /// Pass a webdriver command to the script thread of the current pipeline
-    /// of a browsing context.
-    ScriptCommand(BrowsingContextId, WebDriverScriptCommand),
-    /// Act as if keys were pressed in the browsing context with the given ID.
-    SendKeys(BrowsingContextId, Vec<WebDriverInputEvent>),
-    /// Act as if keys were pressed or release in the browsing context with the given ID.
-    KeyboardAction(BrowsingContextId, KeyboardEvent),
-    /// Act as if the mouse was clicked in the browsing context with the given ID.
-    MouseButtonAction(MouseButtonAction, MouseButton, f32, f32),
-    /// Act as if the mouse was moved in the browsing context with the given ID.
-    MouseMoveAction(f32, f32),
-    /// Set the window size.
-    SetWindowSize(
-        TopLevelBrowsingContextId,
-        DeviceIntSize,
-        IpcSender<WindowSizeData>,
-    ),
-    /// Take a screenshot of the window.
-    TakeScreenshot(
-        TopLevelBrowsingContextId,
-        Option<Rect<f32, CSSPixel>>,
-        IpcSender<Option<Image>>,
-    ),
-    /// Create a new webview that loads about:blank. The constellation will use
-    /// the provided channels to return the top level browsing context id
-    /// associated with the new webview, and a notification when the initial
-    /// load is complete.
-    NewWebView(
-        WebViewId,
-        IpcSender<TopLevelBrowsingContextId>,
-        IpcSender<LoadStatus>,
-    ),
-    /// Close the webview associated with the provided id.
-    CloseWebView(TopLevelBrowsingContextId),
-    /// Focus the webview associated with the provided id.
-    FocusWebView(TopLevelBrowsingContextId),
-}
-
 /// Resources required by workerglobalscopes
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct WorkerGlobalScopeInit {