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/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

@@ -0,0 +1,191 @@
+/* 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/. */
+
+#![allow(missing_docs)]
+
+use std::collections::HashMap;
+
+use base::id::{BrowsingContextId, WebViewId};
+use cookie::Cookie;
+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 {
+    AddCookie(
+        #[serde(
+            deserialize_with = "::hyper_serde::deserialize",
+            serialize_with = "::hyper_serde::serialize"
+        )]
+        Cookie<'static>,
+        IpcSender<Result<(), WebDriverCookieError>>,
+    ),
+    DeleteCookies(IpcSender<Result<(), ErrorStatus>>),
+    ExecuteScript(String, IpcSender<WebDriverJSResult>),
+    ExecuteAsyncScript(String, IpcSender<WebDriverJSResult>),
+    FindElementCSS(String, IpcSender<Result<Option<String>, ErrorStatus>>),
+    FindElementLinkText(String, bool, IpcSender<Result<Option<String>, ErrorStatus>>),
+    FindElementTagName(String, IpcSender<Result<Option<String>, ErrorStatus>>),
+    FindElementsCSS(String, IpcSender<Result<Vec<String>, ErrorStatus>>),
+    FindElementsLinkText(String, bool, IpcSender<Result<Vec<String>, ErrorStatus>>),
+    FindElementsTagName(String, IpcSender<Result<Vec<String>, ErrorStatus>>),
+    FindElementElementCSS(
+        String,
+        String,
+        IpcSender<Result<Option<String>, ErrorStatus>>,
+    ),
+    FindElementElementLinkText(
+        String,
+        String,
+        bool,
+        IpcSender<Result<Option<String>, ErrorStatus>>,
+    ),
+    FindElementElementTagName(
+        String,
+        String,
+        IpcSender<Result<Option<String>, ErrorStatus>>,
+    ),
+    FindElementElementsCSS(String, String, IpcSender<Result<Vec<String>, ErrorStatus>>),
+    FindElementElementsLinkText(
+        String,
+        String,
+        bool,
+        IpcSender<Result<Vec<String>, ErrorStatus>>,
+    ),
+    FindElementElementsTagName(String, String, IpcSender<Result<Vec<String>, ErrorStatus>>),
+    FocusElement(String, IpcSender<Result<(), ErrorStatus>>),
+    ElementClick(String, IpcSender<Result<Option<String>, ErrorStatus>>),
+    GetActiveElement(IpcSender<Option<String>>),
+    GetCookie(String, IpcSender<Vec<Serde<Cookie<'static>>>>),
+    GetCookies(IpcSender<Vec<Serde<Cookie<'static>>>>),
+    GetElementAttribute(
+        String,
+        String,
+        IpcSender<Result<Option<String>, ErrorStatus>>,
+    ),
+    GetElementProperty(
+        String,
+        String,
+        IpcSender<Result<WebDriverJSValue, ErrorStatus>>,
+    ),
+    GetElementCSS(String, String, IpcSender<Result<String, 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<UntypedRect<f32>, ErrorStatus>>),
+    GetBrowsingContextId(
+        WebDriverFrameId,
+        IpcSender<Result<BrowsingContextId, ErrorStatus>>,
+    ),
+    GetUrl(IpcSender<ServoUrl>),
+    GetPageSource(IpcSender<Result<String, ErrorStatus>>),
+    IsEnabled(String, IpcSender<Result<bool, ErrorStatus>>),
+    IsSelected(String, IpcSender<Result<bool, ErrorStatus>>),
+    GetTitle(IpcSender<String>),
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum WebDriverCookieError {
+    InvalidDomain,
+    UnableToSetCookie,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub enum WebDriverJSValue {
+    Undefined,
+    Null,
+    Boolean(bool),
+    Int(i32),
+    Number(f64),
+    String(String),
+    Element(WebElement),
+    Frame(WebFrame),
+    Window(WebWindow),
+    ArrayLike(Vec<WebDriverJSValue>),
+    Object(HashMap<String, WebDriverJSValue>),
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum WebDriverJSError {
+    /// Occurs when handler received an event message for a layout channel that is not
+    /// associated with the current script thread
+    BrowsingContextNotFound,
+    JSError,
+    StaleElementReference,
+    Timeout,
+    UnknownType,
+}
+
+pub type WebDriverJSResult = Result<WebDriverJSValue, WebDriverJSError>;
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum WebDriverFrameId {
+    Short(u16),
+    Element(String),
+    Parent,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum WebDriverLoadStatus {
+    Complete,
+    Timeout,
+    Canceled,
+}