Auto merge of #8971 - jdm:expose-css-errors-1, r=jdm

Add pipeline information to CSS error reporting.

Rebase of #8838.

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/8971)
<!-- Reviewable:end -->

1 files changed, 29 insertions, 1 deletions

diff --git a/components/script/script_task.rs b/components/script/script_task.rs
index c4efab48169..3c54259fc3e 100644
--- a/components/script/script_task.rs
+++ b/components/script/script_task.rs
@@ -592,6 +592,14 @@ pub unsafe extern "C" fn shadow_check_callback(_cx: *mut JSContext,
     DOMProxyShadowsResult::ShadowCheckFailed
 }
 
+#[derive(JSTraceable, HeapSizeOf)]
+pub struct CSSError {
+    filename: String,
+    line: usize,
+    column: usize,
+    msg: String
+}
+
 impl ScriptTask {
     pub fn page_fetch_complete(id: PipelineId, subpage: Option<SubpageId>, metadata: Metadata)
                                -> Option<ParserRoot> {
@@ -1009,7 +1017,9 @@ impl ScriptTask {
             ConstellationControlMsg::GetCurrentState(sender, pipeline_id) => {
                 let state = self.handle_get_current_state(pipeline_id);
                 sender.send(state).unwrap();
-            }
+            },
+            ConstellationControlMsg::ReportCSSError(pipeline_id, filename, line, column, msg) =>
+                self.handle_css_error_reporting(pipeline_id, filename, line, column, msg),
         }
     }
 
@@ -2054,6 +2064,24 @@ impl ScriptTask {
         // script runs?
         self.notify_devtools(document.Title(), (*final_url).clone(), (id, None));
     }
+
+    fn handle_css_error_reporting(&self, pipeline_id: PipelineId, filename: String,
+                                  line: usize, column: usize, msg: String) {
+        let parent_page = self.root_page();
+        let page = match parent_page.find(pipeline_id) {
+            Some(page) => page,
+            None => return,
+        };
+
+        let document = page.document();
+        let css_error = CSSError {
+            filename: filename,
+            line: line,
+            column: column,
+            msg: msg
+        };
+        document.report_css_error(css_error);
+    }
 }
 
 impl Drop for ScriptTask {