[webdriver] Move Webdriver to ServoShell (#36714)

Moving `webdriver` to `servoshell`:

- Let `servoshell` manage lifecycle of `webdriver`
- One by one, move the handling of webdriver commands from
`constellation` to `embedder`

Partially fix: https://github.com/servo/servo/issues/37370
Partially fix webdriver test timeout with `no_top_browsing_context`

cc: @xiaochengh

---------

Signed-off-by: batu_hoang <longvatrong111@gmail.com>

ports/servoshell/desktop/app.rs

@@ -12,13 +12,14 @@ use std::time::Instant;
 use std::{env, fs};
 
 use ::servo::ServoBuilder;
+use crossbeam_channel::unbounded;
 use log::{info, trace, warn};
 use net::protocols::ProtocolRegistry;
-use servo::EventLoopWaker;
 use servo::config::opts::Opts;
 use servo::config::prefs::Preferences;
 use servo::servo_url::ServoUrl;
 use servo::user_content_manager::{UserContentManager, UserScript};
+use servo::{EventLoopWaker, WebDriverCommandMsg};
 use url::Url;
 use winit::application::ApplicationHandler;
 use winit::event::WindowEvent;
@@ -154,10 +155,28 @@ impl App {
         let servo = servo_builder.build();
         servo.setup_logging();
 
+        // Initialize WebDriver server here before `servo` is moved.
+        let webdriver_receiver = self.opts.webdriver_port.map(|port| {
+            let (embedder_sender, embedder_receiver) = unbounded();
+
+            // TODO: WebDriver will no longer need this channel once all WebDriver
+            // commands are executed via the Servo API.
+            let constellation_sender_deprecated = servo.constellation_sender();
+            webdriver_server::start_server(
+                port,
+                constellation_sender_deprecated,
+                embedder_sender,
+                self.waker.clone(),
+            );
+
+            embedder_receiver
+        });
+
         let running_state = Rc::new(RunningAppState::new(
             servo,
             window.clone(),
             self.servoshell_preferences.clone(),
+            webdriver_receiver,
         ));
         running_state.new_toplevel_webview(self.initial_url.clone().into_url());
 
@@ -296,6 +315,49 @@ impl App {
             }
         }
     }
+
+    fn handle_webdriver_messages(&mut self) {
+        let AppState::Running(running_state) = &self.state else {
+            return;
+        };
+
+        let Some(webdriver_receiver) = running_state.webdriver_receiver() else {
+            return;
+        };
+
+        while let Ok(msg) = webdriver_receiver.try_recv() {
+            match msg {
+                WebDriverCommandMsg::IsWebViewOpen(webview_id, sender) => {
+                    let context = running_state.webview_by_id(webview_id);
+                    sender.send(context.is_some()).unwrap();
+                },
+                webdriver_msg @ WebDriverCommandMsg::IsBrowsingContextOpen(..) => {
+                    running_state.forward_webdriver_command(webdriver_msg);
+                },
+                WebDriverCommandMsg::CloseWebView(webview_id) => {
+                    running_state.close_webview(webview_id);
+                },
+                WebDriverCommandMsg::GetWindowSize(..) |
+                WebDriverCommandMsg::FocusWebView(..) |
+                WebDriverCommandMsg::LoadUrl(..) |
+                WebDriverCommandMsg::ScriptCommand(..) |
+                WebDriverCommandMsg::SendKeys(..) |
+                WebDriverCommandMsg::KeyboardAction(..) |
+                WebDriverCommandMsg::MouseButtonAction(..) |
+                WebDriverCommandMsg::MouseMoveAction(..) |
+                WebDriverCommandMsg::WheelScrollAction(..) |
+                WebDriverCommandMsg::SetWindowSize(..) |
+                WebDriverCommandMsg::TakeScreenshot(..) |
+                WebDriverCommandMsg::NewWebView(..) |
+                WebDriverCommandMsg::Refresh(..) => {
+                    warn!(
+                        "WebDriverCommand {:?} is still not moved from constellation to embedder",
+                        msg
+                    );
+                },
+            };
+        }
+    }
 }
 
 impl ApplicationHandler<WakerEvent> for App {
@@ -435,6 +497,9 @@ impl ApplicationHandler<WakerEvent> for App {
         // Consume and handle any events from the Minibrowser.
         self.handle_servoshell_ui_events();
 
+        // Consume and handle any events from the WebDriver.
+        self.handle_webdriver_messages();
+
         self.handle_events_with_winit(event_loop, window);
     }
 

ports/servoshell/desktop/app_state.rs

@@ -7,6 +7,7 @@ use std::collections::HashMap;
 use std::path::PathBuf;
 use std::rc::Rc;
 
+use crossbeam_channel::Receiver;
 use euclid::Vector2D;
 use keyboard_types::{Key, Modifiers, ShortcutMatcher};
 use log::{error, info};
@@ -18,7 +19,7 @@ use servo::webrender_api::units::{DeviceIntPoint, DeviceIntSize};
 use servo::{
     AllowOrDenyRequest, AuthenticationRequest, FilterPattern, FormControl, GamepadHapticEffectType,
     KeyboardEvent, LoadStatus, PermissionRequest, Servo, ServoDelegate, ServoError, SimpleDialog,
-    TouchEventType, WebView, WebViewBuilder, WebViewDelegate,
+    TouchEventType, WebDriverCommandMsg, WebView, WebViewBuilder, WebViewDelegate,
 };
 use url::Url;
 
@@ -44,6 +45,9 @@ pub(crate) struct RunningAppState {
     /// The preferences for this run of servoshell. This is not mutable, so doesn't need to
     /// be stored inside the [`RunningAppStateInner`].
     servoshell_preferences: ServoShellPreferences,
+    /// A [`Receiver`] for receiving commands from a running WebDriver server, if WebDriver
+    /// was enabled.
+    webdriver_receiver: Option<Receiver<WebDriverCommandMsg>>,
     inner: RefCell<RunningAppStateInner>,
 }
 
@@ -88,11 +92,13 @@ impl RunningAppState {
         servo: Servo,
         window: Rc<dyn WindowPortsMethods>,
         servoshell_preferences: ServoShellPreferences,
+        webdriver_receiver: Option<Receiver<WebDriverCommandMsg>>,
     ) -> RunningAppState {
         servo.set_delegate(Rc::new(ServoShellServoDelegate));
         RunningAppState {
             servo,
             servoshell_preferences,
+            webdriver_receiver,
             inner: RefCell::new(RunningAppStateInner {
                 webviews: HashMap::default(),
                 creation_order: Default::default(),
@@ -132,6 +138,14 @@ impl RunningAppState {
         &self.servo
     }
 
+    pub(crate) fn webdriver_receiver(&self) -> Option<&Receiver<WebDriverCommandMsg>> {
+        self.webdriver_receiver.as_ref()
+    }
+
+    pub(crate) fn forward_webdriver_command(&self, command: WebDriverCommandMsg) {
+        self.servo().execute_webdriver_command(command);
+    }
+
     pub(crate) fn hidpi_scale_factor_changed(&self) {
         let inner = self.inner();
         let new_scale_factor = inner.window.hidpi_scale_factor();
@@ -261,6 +275,10 @@ impl RunningAppState {
             .collect()
     }
 
+    pub fn webview_by_id(&self, id: WebViewId) -> Option<WebView> {
+        self.inner().webviews.get(&id).cloned()
+    }
+
     pub fn handle_gamepad_events(&self) {
         let Some(active_webview) = self.focused_webview() else {
             return;