Auto merge of #23951 - georgeroman:return_errorstatus_from_webdriverhandlers, r=jdm

Return ErrorStatus from webdriver_handlers

<!-- Please describe your changes on the following line: -->
With `webdriver 0.40`, `ErrorStatus` implements `Deserialize`. Now we can accommodate for multiple errors occuring in `webdriver_handlers`.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

<!-- Either: -->

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/23951)
<!-- Reviewable:end -->

components/script/script_thread.rs

@@ -687,6 +687,9 @@ pub struct ScriptThread {
 
     /// A mechanism to force the compositor's event loop to process events.
     event_loop_waker: Option<Box<dyn EventLoopWaker>>,
+
+    /// A set of all nodes ever created in this script thread
+    node_ids: DomRefCell<HashSet<String>>,
 }
 
 /// In the event of thread panic, all data on the stack runs its destructor. However, there
@@ -1183,6 +1186,25 @@ impl ScriptThread {
         })
     }
 
+    pub fn save_node_id(node_id: String) {
+        SCRIPT_THREAD_ROOT.with(|root| {
+            if let Some(script_thread) = root.get() {
+                let script_thread = unsafe { &*script_thread };
+                script_thread.node_ids.borrow_mut().insert(node_id);
+            }
+        })
+    }
+
+    pub fn has_node_id(node_id: &str) -> bool {
+        SCRIPT_THREAD_ROOT.with(|root| match root.get() {
+            Some(script_thread) => {
+                let script_thread = unsafe { &*script_thread };
+                script_thread.node_ids.borrow().contains(node_id)
+            },
+            None => false,
+        })
+    }
+
     /// Creates a new script thread.
     pub fn new(
         state: InitialScriptState,
@@ -1315,6 +1337,8 @@ impl ScriptThread {
             user_agent,
             player_context: state.player_context,
             event_loop_waker: state.event_loop_waker,
+
+            node_ids: Default::default(),
         }
     }