Auto merge of #10551 - asajeffrey:trigger-mozbrowsererror-event, r=jdm

Trigger mozbrowsererror event when a pipeline fails.

Addresses part of #10334 (it fires the event, but does not include a backtrace).

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1 files changed, 44 insertions, 16 deletions

diff --git a/components/compositing/constellation.rs b/components/compositing/constellation.rs
index 0e65c36ecf3..3cd67edcbcd 100644
--- a/components/compositing/constellation.rs
+++ b/components/compositing/constellation.rs
@@ -873,6 +873,9 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
 
         let window_size = self.pipelines.get(&failure.pipeline_id).and_then(|pipeline| pipeline.size);
 
+        // Notify the browser chrome that the pipeline has failed
+        self.trigger_mozbrowsererror(failure.pipeline_id);
+
         self.close_pipeline(failure.pipeline_id, ExitPipelineMode::Force);
 
         while let Some(pending_pipeline_id) = self.pending_frames.iter().find(|pending| {
@@ -1916,30 +1919,54 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
     }
 
     // https://developer.mozilla.org/en-US/docs/Web/Events/mozbrowserlocationchange
+    // Note that this is a no-op if the pipeline is not an immediate child iframe of the root
     fn trigger_mozbrowserlocationchange(&self, pipeline_id: PipelineId) {
-        if prefs::get_pref("dom.mozbrowser.enabled").as_boolean().unwrap_or(false) {
-            let event_info = self.pipelines.get(&pipeline_id).and_then(|pipeline| {
-                pipeline.parent_info.map(|(containing_pipeline_id, subpage_id)| {
-                    (containing_pipeline_id, subpage_id, pipeline.url.serialize())
-                })
-            });
+        if !prefs::get_pref("dom.mozbrowser.enabled").as_boolean().unwrap_or(false) { return; }
 
-            // If this is an iframe, then send the event with new url
-            if let Some((containing_pipeline_id, subpage_id, url)) = event_info {
-                if let Some(parent_pipeline) = self.pipelines.get(&containing_pipeline_id) {
-                    if let Some(frame_id) = self.pipeline_to_frame_map.get(&pipeline_id) {
-                        if let Some(frame) = self.frames.get(&frame_id) {
-                            let can_go_backward = !frame.prev.is_empty();
-                            let can_go_forward = !frame.next.is_empty();
-                            let event = MozBrowserEvent::LocationChange(url, can_go_backward, can_go_forward);
-                            parent_pipeline.trigger_mozbrowser_event(subpage_id, event);
-                        }
+        let event_info = self.pipelines.get(&pipeline_id).and_then(|pipeline| {
+            pipeline.parent_info.map(|(containing_pipeline_id, subpage_id)| {
+                (containing_pipeline_id, subpage_id, pipeline.url.serialize())
+            })
+        });
+
+        // If this is an iframe, then send the event with new url
+        if let Some((containing_pipeline_id, subpage_id, url)) = event_info {
+            if let Some(parent_pipeline) = self.pipelines.get(&containing_pipeline_id) {
+                if let Some(frame_id) = self.pipeline_to_frame_map.get(&pipeline_id) {
+                    if let Some(frame) = self.frames.get(&frame_id) {
+                        let can_go_backward = !frame.prev.is_empty();
+                        let can_go_forward = !frame.next.is_empty();
+                        let event = MozBrowserEvent::LocationChange(url, can_go_backward, can_go_forward);
+                        parent_pipeline.trigger_mozbrowser_event(subpage_id, event);
                     }
                 }
             }
         }
     }
 
+    // https://developer.mozilla.org/en-US/docs/Web/Events/mozbrowsererror
+    // Note that this does not require the pipeline to be an immediate child of the root
+    // TODO: propagate more error information, e.g. a backtrace
+    fn trigger_mozbrowsererror(&self, pipeline_id: PipelineId) {
+        if !prefs::get_pref("dom.mozbrowser.enabled").as_boolean().unwrap_or(false) { return; }
+
+        if let Some(pipeline) = self.pipelines.get(&pipeline_id) {
+            if let Some(mut ancestor_info) = pipeline.parent_info {
+                if let Some(mut ancestor) = self.pipelines.get(&ancestor_info.0) {
+                    while let Some(next_info) = ancestor.parent_info {
+                        ancestor_info = next_info;
+                        ancestor = match self.pipelines.get(&ancestor_info.0) {
+                            Some(ancestor) => ancestor,
+                            None => return warn!("Mozbrowsererror via closed pipeline {:?}.", ancestor_info.0),
+                        };
+                    }
+                    let event = MozBrowserEvent::Error;
+                    ancestor.trigger_mozbrowser_event(ancestor_info.1, event);
+                }
+            }
+        }
+    }
+
     fn focused_pipeline_in_tree(&self, frame_id: FrameId) -> bool {
         self.focus_pipeline_id.map_or(false, |pipeline_id| {
             self.pipeline_exists_in_tree(pipeline_id, Some(frame_id))
@@ -1956,4 +1983,5 @@ impl<LTF: LayoutThreadFactory, STF: ScriptThreadFactory> Constellation<LTF, STF>
         self.current_frame_tree_iter(root_frame_id)
             .any(|current_frame| current_frame.current == pipeline_id)
     }
+
 }