Auto merge of #20181 - fabricedesre:end-load-pageshow, r=jdm

Fire the pageshow event at the end of the page load

<!-- Please describe your changes on the following line: -->
This implements step 8 of https://html.spec.whatwg.org/multipage/parsing.html#the-end

---
<!-- 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` 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 I could not find a wpt test for that, which is strange. I likely missed it :(

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

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

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components/atoms/static_atoms.txt

@@ -47,6 +47,7 @@ none
 number
 onchange
 open
+pageshow
 password
 pause
 play

components/script/dom/document.rs

@@ -364,6 +364,8 @@ pub struct Document {
     canceller: FetchCanceller,
     /// https://html.spec.whatwg.org/multipage/#throw-on-dynamic-markup-insertion-counter
     throw_on_dynamic_markup_insertion_counter: Cell<u64>,
+    /// https://html.spec.whatwg.org/multipage/#page-showing
+    page_showing: Cell<bool>,
 }
 
 #[derive(JSTraceable, MallocSizeOf)]
@@ -1634,7 +1636,37 @@ impl Document {
         ).unwrap();
 
         // Step 8.
-        // TODO: pageshow event.
+        let document = Trusted::new(self);
+        if document.root().browsing_context().is_some() {
+            self.window.dom_manipulation_task_source().queue(
+                task!(fire_pageshow_event: move || {
+                    let document = document.root();
+                    let window = document.window();
+                    if document.page_showing.get() || !window.is_alive() {
+                        return;
+                    }
+
+                    document.page_showing.set(true);
+
+                    let event = PageTransitionEvent::new(
+                        window,
+                        atom!("pageshow"),
+                        false, // bubbles
+                        false, // cancelable
+                        false, // persisted
+                    );
+                    let event = event.upcast::<Event>();
+                    event.set_trusted(true);
+
+                    // FIXME(nox): Why are errors silenced here?
+                    let _ = window.upcast::<EventTarget>().dispatch_event_with_target(
+                        document.upcast(),
+                        &event,
+                    );
+                }),
+                self.window.upcast(),
+            ).unwrap();
+        }
 
         // Step 9.
         // TODO: pending application cache download process tasks.
@@ -2225,6 +2257,7 @@ impl Document {
             tti_window: DomRefCell::new(InteractiveWindow::new()),
             canceller: canceller,
             throw_on_dynamic_markup_insertion_counter: Cell::new(0),
+            page_showing: Cell::new(false),
         }
     }
 

tests/wpt/metadata/MANIFEST.json

@@ -568154,7 +568154,7 @@
    "support"
   ],
   "html/syntax/parsing/the-end.html": [
-   "78b17f053dd3e52b3bf68a5fafc4a4e070e65cfd",
+   "4b38fe0c7bcb088450cc13f13c805711caf91961",
    "testharness"
   ],
   "html/syntax/serializing-html-fragments/.gitkeep": [

tests/wpt/web-platform-tests/html/syntax/parsing/the-end.html

@@ -29,12 +29,28 @@ async_test(function() {
 }, "load");
 
 async_test(function() {
-  var seen = false;
-  document.addEventListener("DOMContentLoaded", this.step_func(function() {
-    seen = true;
+  window.addEventListener("pageshow", this.step_func_done(function(e) {
+    assert_equals(e.type, "pageshow");
+    assert_false(e.bubbles, "bubbles should be false");
+    assert_false(e.cancelable, "cancelable should be false");
+    assert_equals(e.target, document, "target should be document");
+    assert_true(e.isTrusted, "isTrusted should be true");
+    assert_class_string(e, "PageTransitionEvent");
   }));
-  window.addEventListener("load", this.step_func_done(function() {
-    assert_true(seen, "DOMContentLoaded should be fired before load");
+}, "pageshow");
+
+async_test(function() {
+  var seen_dcl = false;
+  var seen_load = false;
+  document.addEventListener("DOMContentLoaded", this.step_func(function() {
+    seen_dcl = true;
+  }));
+  window.addEventListener("load", this.step_func(function() {
+    seen_load = true;
+    assert_true(seen_dcl, "DOMContentLoaded should be fired before load");
+  }));
+  window.addEventListener("pageshow", this.step_func_done(function() {
+    assert_true(seen_load, "load should be fired before pageshow")
   }));
 }, "order");
 </script>