[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_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;