Auto merge of #11366 - Ms2ger:css_errors_store, r=SimonSapin

Stop storing CSS errors on the Document.

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 --faster` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

Either:
- [ ] There are tests for these changes OR
- [x] These changes do not require tests because removing dead code

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

They are never read.

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components/script/dom/document.rs

@@ -2,7 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use devtools_traits::CSSError;
 use document_loader::{DocumentLoader, LoadType};
 use dom::activation::{ActivationSource, synthetic_click_activation};
 use dom::attr::{Attr, AttrValue};
@@ -232,8 +231,6 @@ pub struct Document {
     dom_complete: Cell<u64>,
     load_event_start: Cell<u64>,
     load_event_end: Cell<u64>,
-    /// Vector to store CSS errors
-    css_errors_store: DOMRefCell<Vec<CSSError>>,
     /// https://html.spec.whatwg.org/multipage/#concept-document-https-state
     https_state: Cell<HttpsState>,
     touchpad_pressure_phase: Cell<TouchpadPressurePhase>,
@@ -332,10 +329,6 @@ impl Document {
         self.trigger_mozbrowser_event(MozBrowserEvent::SecurityChange(https_state));
     }
 
-    pub fn report_css_error(&self, css_error: CSSError) {
-        self.css_errors_store.borrow_mut().push(css_error);
-    }
-
     // https://html.spec.whatwg.org/multipage/#fully-active
     pub fn is_fully_active(&self) -> bool {
         let browsing_context = match self.browsing_context() {
@@ -1705,7 +1698,6 @@ impl Document {
             dom_complete: Cell::new(Default::default()),
             load_event_start: Cell::new(Default::default()),
             load_event_end: Cell::new(Default::default()),
-            css_errors_store: DOMRefCell::new(vec![]),
             https_state: Cell::new(HttpsState::None),
             touchpad_pressure_phase: Cell::new(TouchpadPressurePhase::BeforeClick),
             origin: origin,

components/script/script_thread.rs

@@ -1971,29 +1971,27 @@ impl ScriptThread {
 
     fn handle_css_error_reporting(&self, pipeline_id: PipelineId, filename: String,
                                   line: usize, column: usize, msg: String) {
+        let sender = match self.devtools_chan {
+            Some(ref sender) => sender,
+            None => return,
+        };
+
         let parent_context = self.root_browsing_context();
         let context = match parent_context.find(pipeline_id) {
             Some(context) => context,
             None => return,
         };
 
-        let document = context.active_document();
+        let window = context.active_window();
+        if window.live_devtools_updates() {
             let css_error = CSSError {
                 filename: filename,
                 line: line,
                 column: column,
                 msg: msg
             };
-
-        document.report_css_error(css_error.clone());
-        let window = context.active_window();
-
-        if window.live_devtools_updates() {
-            if let Some(ref chan) = self.devtools_chan {
-                chan.send(ScriptToDevtoolsControlMsg::ReportCSSError(
-                    pipeline_id,
-                    css_error)).unwrap();
-             }
+            let message = ScriptToDevtoolsControlMsg::ReportCSSError(pipeline_id, css_error);
+            sender.send(message).unwrap();
         }
     }
 }