Fire the navigate event earlier for cross-document traversals

This earlier timing ensures that we fire the navigate event in the old document when a traversal is served from the bfcache, and is more consistent with non-history cross-document navigate events. Currently, cross-document traversals fire the navigate event at the last possible time: during commit in the renderer, the navigate event is fired in the old document immediately before it is unloaded. The navigate event is not allowed to cancel or intercept a cross-document traversal, otherwise this timing would be too late. We did not reach a firm conclusion on when to fire the navigate event for cross-document traversals during the design of the Navigation API (see WICG/navigation-api#207), and this was the latest of the options considered. This timing has two problems: 1. Traversals served by the back forward cache don't "commit". So the navigate event is erroneously omitted. 2. The navigate event fires after redirects, where for other cross-document navigations, it fires before redirects. This CL adds plumbing for the browser to trigger the navigate event to fire in the renderer in the cross-document traversal case, and moves the time of the navigate event earlier. It now fires after the browser process has decided to allow the traversal to start (i.e., after beforeunload has been fired in any relevant frames, and after start throttles). In the cross-document traversal case where the navigation is not served from bfcache, this will fire the navigate event in parallel with the network request (which is ok because the navigate event can't intercept or cancel the navigation, this timing would not be permissible for other navigation types where the navigate event has more power over the navigation). In the case where no network request is needed (bfcache, about:blank, etc.), the navigate event task gets sent to the renderer immediately before the commit/activation task. Bug: 1475907 Change-Id: I1ef7337e2d85f9cdbfc0110f9f4fe3bcd4dea75d
web-platform-tests · Nov 20, 2023 · 735468f · 735468f
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commit 735468f
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Showing 4 changed files with 66 additions and 6 deletions.
diff --git a/navigation-api/navigate-event/navigate-history-back-bfcache.html b/navigation-api/navigate-event/navigate-history-back-bfcache.html
@@ -0,0 +1,24 @@
+<!doctype html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>
+
+<script>
+runBfcacheTest({
+  targetOrigin: originSameOrigin,
+  funcBeforeBackNavigation: () => {
+    window.did_navigate = false;
+    navigation.onnavigate = () => window.did_navigate = true;
+  },
+  async funcAfterAssertion(pageA, pageB) {
+    // When `funcAfterAssertion` is called, we've already navigated to pageB,
+    // then gone back to pageA with bfcache. Now go forward to pageB so we can
+    // observe whether the navigate event fired.
+    await pageA.execute_script(() => history.forward());
+    await pageB.execute_script(waitForPageShow);
+    assert_true(await pageB.execute_script(() => window.did_navigate));
+  }
+}, "navigate event should fire when traversing to a bfcache hit");
+</script>
diff --git a/navigation-api/navigation-methods/return-value/back-204-205-download.html b/navigation-api/navigation-methods/return-value/back-204-205-download.html
@@ -32,11 +32,9 @@
 
     const indexBefore = i.contentWindow.navigation.currentEntry.index;
 
-    // One might be surprised that navigate does not fire. (It does fire for the
-    // corresponding tests of navigation.navigate(), i.e., this is
-    // traversal-specific behavior.) See https://github.com/WICG/navigation-api/issues/207
-    // for some discussion.
-    i.contentWindow.navigation.onnavigate = t.unreached_func("onnavigate should not be called");
+    let onnavigate_called = false;
+    i.contentWindow.navigation.onnavigate = () => onnavigate_called = true;
+    i.contentWindow.onunload = t.unreached_func("onunload should not be called");
     i.contentWindow.navigation.onnavigatesuccess = t.unreached_func("onnavigatesuccess should not be called");
     i.contentWindow.navigation.onnavigateerror = t.unreached_func("onnavigateerror should not be called");
 
@@ -47,6 +45,7 @@
     await new Promise(resolve => t.step_timeout(resolve, 50));
     assert_equals(i.contentWindow.navigation.currentEntry.index, indexBefore);
     assert_equals(i.contentWindow.navigation.transition, null);
+    assert_true(onnavigate_called);
   }, `back() promises to ${description} never settle`);
 }
 </script>
diff --git a/navigation-api/ordering-and-transition/back-cross-document-event-order.html b/navigation-api/ordering-and-transition/back-cross-document-event-order.html
@@ -0,0 +1,36 @@
+<!doctype html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<iframe id="i" src="resources/notify-top-early.html"></iframe>
+<script>
+async_test(t => {
+  let events = [];
+  function finish() {
+    assert_array_equals(events, ["onnavigate", "onunload", "readystateinteractive", "domcontentloaded", "readystatecomplete", "onload", "onpageshow"]);
+    t.done();
+  };
+
+  window.onload = t.step_func(() => {
+    i.contentWindow.navigation.navigate("?1");
+    i.onload = t.step_func(() => {
+      window.childStarted = () => {
+        i.contentWindow.navigation.onnavigatesuccess = () => events.push("onnavigatesuccess");
+        i.contentWindow.navigation.onnavigateerror = () => events.push("onnavigateerror");
+        i.contentWindow.onpageshow = () => events.push("onpageshow");
+        i.contentWindow.onhashchange = () => events.push("onhashchange");
+        i.contentWindow.onpopstate = () => events.push("onpopstate");
+        i.onload = t.step_func(() => {
+          events.push("onload");
+          t.step_timeout(finish, 0);
+        });
+        i.contentDocument.addEventListener("DOMContentLoaded", () => events.push("domcontentloaded"));
+        i.contentDocument.onreadystatechange = () => events.push("readystate" + i.contentDocument.readyState);
+      };
+      i.contentWindow.onunload = () => events.push("onunload");
+      i.contentWindow.navigation.onnavigate = () => events.push("onnavigate");
+      i.contentWindow.navigation.back().committed.then(
+        () => events.push("promisefulfilled"), () => events.push("promiserejected"));
+    })
+  });
+}, "back() event ordering for cross-document traversal");
+</script>
diff --git a/navigation-api/ordering-and-transition/navigate-cross-document-event-order.html b/navigation-api/ordering-and-transition/navigate-cross-document-event-order.html
@@ -6,7 +6,7 @@
 async_test(t => {
   let events = [];
   function finish() {
-    assert_array_equals(events, ["onnavigate", "readystateinteractive", "domcontentloaded", "readystatecomplete", "onload", "onpageshow"]);
+    assert_array_equals(events, ["onnavigate", "onunload", "readystateinteractive", "domcontentloaded", "readystatecomplete", "onload", "onpageshow"]);
     t.done();
   };
 
@@ -24,6 +24,7 @@
       i.contentDocument.addEventListener("DOMContentLoaded", () => events.push("domcontentloaded"));
       i.contentDocument.onreadystatechange = () => events.push("readystate" + i.contentDocument.readyState);
     };
+    i.contentWindow.onunload = () => events.push("onunload");
     i.contentWindow.navigation.onnavigate = () => events.push("onnavigate");
     i.contentWindow.navigation.navigate("?1").committed.then(
         () => events.push("promisefulfilled"), () => events.push("promiserejected"));