script: Fix a few load related bugs.

This is what was making me hit the new test failures. So turns out that when the
DOMContentLoaded event is fired we fired no messages to the constellation, but
we fired the DOMLoad message from the DocumentProgressHandler, effectively after
having dispatched the Load message from script thread.

This also fixes the possibility of a subframe navigation not blocking the load
event of the parent document, for example.

components/compositing/compositor.rs

@@ -2114,7 +2114,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
                 }
 
                 // Check if there are any pending frames. If so, the image is not stable yet.
-                if self.pending_subpages.len() > 0 {
+                if !self.pending_subpages.is_empty() {
                     return Err(NotReadyToPaint::PendingSubpages(self.pending_subpages.len()));
                 }
 

components/constellation/constellation.rs

@@ -1441,6 +1441,7 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             let root = self.root_frame_id.is_none() || self.root_frame_id == Some(frame_id);
             self.compositor_proxy.send(ToCompositorMsg::LoadComplete(back, forward, root));
         }
+        self.handle_subframe_loaded(pipeline_id);
     }
 
     fn handle_dom_load(&mut self, pipeline_id: PipelineId) {
@@ -1455,8 +1456,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
         if webdriver_reset {
             self.webdriver.load_channel = None;
         }
-
-        self.handle_subframe_loaded(pipeline_id);
     }
 
     fn handle_traverse_history_msg(&mut self,
@@ -2073,7 +2072,7 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
         }
 
         // If there are pending loads, wait for those to complete.
-        if self.pending_frames.len() > 0 {
+        if !self.pending_frames.is_empty() {
             return ReadyToSave::PendingFrames;
         }
 
@@ -2089,7 +2088,10 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             let pipeline_id = frame.current.0;
 
             let pipeline = match self.pipelines.get(&pipeline_id) {
-                None => { warn!("Pipeline {:?} screenshot while closing.", pipeline_id); continue; },
+                None => {
+                    warn!("Pipeline {:?} screenshot while closing.", pipeline_id);
+                    continue;
+                },
                 Some(pipeline) => pipeline,
             };
 

components/script/dom/document.rs

@@ -376,6 +376,7 @@ impl Document {
         // that workable.
         match self.GetDocumentElement() {
             Some(root) => {
+                root.upcast::<Node>().is_dirty() ||
                 root.upcast::<Node>().has_dirty_descendants() ||
                 !self.modified_elements.borrow().is_empty()
             }
@@ -1371,6 +1372,7 @@ impl Document {
     }
 
     pub fn finish_load(&self, load: LoadType) {
+        debug!("Document got finish_load: {:?}", load);
         // The parser might need the loader, so restrict the lifetime of the borrow.
         {
             let mut loader = self.loader.borrow_mut();
@@ -1396,7 +1398,7 @@ impl Document {
             // If we don't have a parser, and the reflow timer has been reset, explicitly
             // trigger a reflow.
             if let LoadType::Stylesheet(_) = load {
-                self.window().reflow(ReflowGoal::ForDisplay,
+                self.window.reflow(ReflowGoal::ForDisplay,
                                    ReflowQueryType::NoQuery,
                                    ReflowReason::StylesheetLoaded);
             }
@@ -1487,6 +1489,8 @@ impl Document {
             return;
         }
         self.domcontentloaded_dispatched.set(true);
+        assert!(self.ReadyState() != DocumentReadyState::Complete,
+                "Complete before DOMContentLoaded?");
 
         update_with_current_time_ms(&self.dom_content_loaded_event_start);
 
@@ -1497,14 +1501,17 @@ impl Document {
                       ReflowQueryType::NoQuery,
                       ReflowReason::DOMContentLoaded);
 
+        let pipeline_id = self.window.pipeline();
+        let event = ConstellationMsg::DOMLoad(pipeline_id);
+        self.window.constellation_chan().send(event).unwrap();
+
         update_with_current_time_ms(&self.dom_content_loaded_event_end);
     }
 
     pub fn notify_constellation_load(&self) {
         let pipeline_id = self.window.pipeline();
-        let event = ConstellationMsg::DOMLoad(pipeline_id);
-        self.window.constellation_chan().send(event).unwrap();
-
+        let load_event = ConstellationMsg::LoadComplete(pipeline_id);
+        self.window.constellation_chan().send(load_event).unwrap();
     }
 
     pub fn set_current_parser(&self, script: Option<ParserRef>) {
@@ -2913,11 +2920,12 @@ impl DocumentProgressHandler {
         // http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-loadEventEnd
         update_with_current_time_ms(&document.load_event_end);
 
-        document.notify_constellation_load();
 
         window.reflow(ReflowGoal::ForDisplay,
                       ReflowQueryType::NoQuery,
                       ReflowReason::DocumentLoaded);
+
+        document.notify_constellation_load();
     }
 }
 

components/script/script_thread.rs

@@ -1193,8 +1193,6 @@ impl ScriptThread {
         // https://html.spec.whatwg.org/multipage/#the-end step 7
         let handler = box DocumentProgressHandler::new(Trusted::new(doc));
         self.dom_manipulation_task_source.queue(handler, GlobalRef::Window(doc.window())).unwrap();
-
-        self.constellation_chan.send(ConstellationMsg::LoadComplete(pipeline)).unwrap();
     }
 
     fn collect_reports(&self, reports_chan: ReportsChan) {