Dispatch load events for cross origin iframes. Resolves #6672.

components/compositing/constellation.rs

@@ -758,6 +758,20 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
         })).unwrap();
     }
 
+    fn handle_subframe_loaded(&mut self, pipeline_id: PipelineId) {
+        let subframe_pipeline = self.pipeline(pipeline_id);
+        let subframe_parent = match subframe_pipeline.parent_info {
+            Some(ref parent) => parent,
+            None => return,
+        };
+        let parent_pipeline = self.pipeline(subframe_parent.0);
+        let msg = ConstellationControlMsg::DispatchFrameLoadEvent {
+            target: pipeline_id,
+            parent: subframe_parent.0
+        };
+        parent_pipeline.script_chan.send(msg).unwrap();
+    }
+
     // The script task associated with pipeline_id has loaded a URL in an iframe via script. This
     // will result in a new pipeline being spawned and a frame tree being added to
     // containing_page_pipeline_id's frame tree's children. This message is never the result of a
@@ -908,6 +922,8 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
         if webdriver_reset {
             self.webdriver.load_channel = None;
         }
+
+        self.handle_subframe_loaded(pipeline_id);
     }
 
     fn handle_navigate_msg(&mut self,

components/msg/constellation_msg.rs

@@ -277,6 +277,8 @@ pub enum ScriptMsg {
                          GLContextAttributes,
                          IpcSender<Result<(IpcSender<CanvasMsg>, usize), String>>),
     /// Dispatched after the DOM load event has fired on a document
+    /// Causes a `load` event to be dispatched to any enclosing frame context element
+    /// for the given pipeline.
     DOMLoad(PipelineId),
     Failure(Failure),
     /// Notifies the constellation that this frame has received focus.

components/script/dom/document.rs

@@ -58,7 +58,7 @@ use dom::keyboardevent::KeyboardEvent;
 use dom::location::Location;
 use dom::messageevent::MessageEvent;
 use dom::mouseevent::MouseEvent;
-use dom::node::{self, CloneChildrenFlag, Node, NodeDamage, window_from_node};
+use dom::node::{self, CloneChildrenFlag, Node, NodeDamage};
 use dom::nodeiterator::NodeIterator;
 use dom::nodelist::NodeList;
 use dom::processinginstruction::ProcessingInstruction;
@@ -79,9 +79,9 @@ use layout_interface::{HitTestResponse, MouseOverResponse};
 use layout_interface::{LayoutChan, Msg};
 use layout_interface::{ReflowGoal, ReflowQueryType};
 use msg::compositor_msg::ScriptToCompositorMsg;
-use msg::constellation_msg::AnimationState;
 use msg::constellation_msg::ScriptMsg as ConstellationMsg;
 use msg::constellation_msg::{ALT, CONTROL, SHIFT, SUPER};
+use msg::constellation_msg::{AnimationState, PipelineId};
 use msg::constellation_msg::{ConstellationChan, FocusType, Key, KeyModifiers, KeyState, MozBrowserEvent, SubpageId};
 use net_traits::ControlMsg::{GetCookiesForUrl, SetCookiesForUrl};
 use net_traits::CookieSource::NonHTTP;
@@ -1333,6 +1333,14 @@ impl Document {
             .find(|node| node.subpage_id() == Some(subpage_id))
     }
 
+    /// Find an iframe element in the document.
+    pub fn find_iframe_by_pipeline(&self, pipeline: PipelineId) -> Option<Root<HTMLIFrameElement>> {
+        self.upcast::<Node>()
+            .traverse_preorder()
+            .filter_map(Root::downcast::<HTMLIFrameElement>)
+            .find(|node| node.pipeline() == Some(pipeline))
+    }
+
     pub fn get_dom_loading(&self) -> u64 {
         self.dom_loading.get()
     }
@@ -2433,18 +2441,6 @@ impl DocumentProgressHandler {
         event.set_trusted(true);
         let _ = wintarget.dispatch_event_with_target(document.upcast(), &event);
 
-        let browsing_context = window.browsing_context();
-        let browsing_context = browsing_context.as_ref().unwrap();
-
-        if let Some(frame_element) = browsing_context.frame_element() {
-            let frame_window = window_from_node(frame_element);
-            let event = Event::new(GlobalRef::Window(frame_window.r()),
-                                   DOMString::from("load"),
-                                   EventBubbles::DoesNotBubble,
-                                   EventCancelable::NotCancelable);
-            event.fire(frame_element.upcast());
-        };
-
         document.notify_constellation_load();
 
         // https://developer.mozilla.org/en-US/docs/Web/Events/mozbrowserloadend

components/script/dom/htmliframeelement.rs

@@ -16,7 +16,7 @@ use dom::bindings::reflector::Reflectable;
 use dom::customevent::CustomEvent;
 use dom::document::Document;
 use dom::element::{AttributeMutation, Element, RawLayoutElementHelpers};
-use dom::event::Event;
+use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::htmlelement::HTMLElement;
 use dom::node::{Node, window_from_node};
 use dom::urlhelper::UrlHelper;
@@ -189,6 +189,29 @@ impl HTMLIFrameElement {
     pub fn subpage_id(&self) -> Option<SubpageId> {
         self.subpage_id.get()
     }
+
+    pub fn pipeline(&self) -> Option<PipelineId> {
+        self.pipeline_id.get()
+    }
+
+    /// https://html.spec.whatwg.org/multipage/#iframe-load-event-steps steps 1-4
+    pub fn iframe_load_event_steps(&self) {
+        // TODO A cross-origin child document would not be easily accessible
+        //      from this script thread. It's unclear how to implement
+        //      steps 2, 3, and 5 efficiently in this case.
+        // TODO Step 2 - check child document `mute iframe load` flag
+        // TODO Step 3 - set child document  `mut iframe load` flag
+
+        // Step 4
+        let window = window_from_node(self);
+        let event = Event::new(GlobalRef::Window(window.r()),
+                               DOMString::from("load".to_owned()),
+                               EventBubbles::DoesNotBubble,
+                               EventCancelable::NotCancelable);
+        event.fire(self.upcast());
+
+        // TODO Step 5 - unset child document `mut iframe load` flag
+    }
 }
 
 pub trait HTMLIFrameElementLayoutMethods {

components/script/script_task.rs

@@ -1006,6 +1006,9 @@ impl ScriptTask {
                 self.handle_tick_all_animations(pipeline_id),
             ConstellationControlMsg::WebFontLoaded(pipeline_id) =>
                 self.handle_web_font_loaded(pipeline_id),
+            ConstellationControlMsg::DispatchFrameLoadEvent {
+                target: pipeline_id, parent: containing_id } =>
+                self.handle_frame_load_event(containing_id, pipeline_id),
             ConstellationControlMsg::GetCurrentState(sender, pipeline_id) => {
                 let state = self.handle_get_current_state(pipeline_id);
                 sender.send(state).unwrap();
@@ -1535,6 +1538,15 @@ impl ScriptTask {
         }
     }
 
+    /// Notify the containing document of a child frame that has completed loading.
+    fn handle_frame_load_event(&self, containing_pipeline: PipelineId, id: PipelineId) {
+        let page = get_page(&self.root_page(), containing_pipeline);
+        let document = page.document();
+        if let Some(iframe) = document.find_iframe_by_pipeline(id) {
+            iframe.iframe_load_event_steps();
+        }
+    }
+
     /// The entry point to document loading. Defines bindings, sets up the window and document
     /// objects, parses HTML and CSS, and kicks off initial layout.
     fn load(&self, metadata: Metadata, incomplete: InProgressLoad) -> Root<ServoHTMLParser> {

components/script_traits/lib.rs

@@ -137,6 +137,13 @@ pub enum ConstellationControlMsg {
     WebFontLoaded(PipelineId),
     /// Get the current state of the script task for a given pipeline.
     GetCurrentState(IpcSender<ScriptState>, PipelineId),
+    /// Cause a `load` event to be dispatched at the appropriate frame element.
+    DispatchFrameLoadEvent {
+        /// The pipeline that has been marked as loaded.
+        target: PipelineId,
+        /// The pipeline that contains a frame loading the target pipeline.
+        parent: PipelineId
+    },
 }
 
 /// The mouse button involved in the event.