Portals: focus() inside portal should change active element

Allows a portal document's activeElement to update when focus is called. Note that focus events won't be dispatched as the portal doesn't get page focus, and the portal WebContents isn't set as the focused WebContents (with the exception of orphaned portals). Updating the activeElement also means an autofocused element inside a portal will receive focus when the portal is activated. More discussion here: WICG/portals#257 Change-Id: If67be1f424114653983b473a80c515337d49596a Bug: 1059404
web-platform-tests · Feb 3, 2021 · 9fcb95a · 9fcb95a
1 parent e3a0136
commit 9fcb95a
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Showing 4 changed files with 78 additions and 3 deletions.
diff --git a/portals/portals-focus.sub.html b/portals/portals-focus.sub.html
@@ -29,6 +29,19 @@
     }
   }, "test that an element inside a portal cannot steal focus");
 
+  promise_test(async () => {
+    let portal = await createPortal(document, new URL("resources/focus-page-with-button.html", location.href));
+    try {
+      let activeElementUpdated = new Promise(r => {
+        portal.onmessage = e => r(e.data.activeElementUpdated)
+      });
+      portal.postMessage('focus-update-active-element');
+      assert_true(await activeElementUpdated);
+    } finally {
+      document.body.removeChild(portal);
+    }
+  }, "test that activeElement inside a portal is updated after focus() is called");
+
   promise_test(async t => {
     let portal = await createPortal(document, new URL("resources/focus-page-with-x-origin-iframe.sub.html", location.href));
     try {
@@ -42,6 +55,19 @@
     }
   }, "test that an element inside a portal's x-origin subframe cannot steal focus");
 
+  promise_test(async () => {
+    let portal = await createPortal(document, new URL("resources/focus-page-with-x-origin-iframe.sub.html", location.href));
+    try {
+      portal.postMessage("focus-update-active-element");
+      let {activeElementUpdated} = await new Promise(r => {
+        portal.onmessage = e => r(e.data);
+      });
+      assert_true(activeElementUpdated);
+    } finally {
+      document.body.removeChild(portal);
+    }
+  }, "test that a portal's x-origin subframe becomes active element on focus");
+
   promise_test(async t => {
     let win = await openBlankPortalHost();
     let doc = win.document;
@@ -87,6 +113,28 @@
     }
   }, "test that a x-origin iframe inside an adopted portal cannot steal focus");
 
+  promise_test(async () => {
+    let win = await openBlankPortalHost();
+    let doc = win.document;
+    try {
+      let portal = await createPortal(doc, new URL("resources/focus-page-with-autofocus.html", location.href));
+      portal.postMessage('check-active-element');
+      let result = await new Promise(r => {
+        portal.onmessage = e => r(e.data);
+      });
+      assert_true(result, "autofocused element is active element");
+
+      await portal.activate();
+      win.portalHost.postMessage('check-active-element');
+      result = await new Promise(r => {
+        win.portalHost.onmessage = e => r(e.data)
+      });
+      assert_true(result, "autofocused element is still active element");
+    } finally {
+      win.close();
+    }
+  }, "test that autofocus inside a portal works");
+
   const TAB = "\ue004"; // https://w3c.github.io/webdriver/#keyboard-actions
   const SPACE = " "
   const RETURN = "\r";

diff --git a/portals/resources/focus-page-with-autofocus.html b/portals/resources/focus-page-with-autofocus.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<body>
+  <button id="one">one</button>
+  <button id="two" autofocus>two</button>
+  <button id="three">three</button>
+  <script>
+    function messageHandler(e) {
+      if (e.data === 'check-active-element') {
+        let autofocusedButton = document.querySelector('#two');
+        e.source.postMessage(document.activeElement === autofocusedButton);
+      }
+    }
+
+    window.portalHost.onmessage = messageHandler;
+    window.onportalactivate = e => {
+      let portal = e.adoptPredecessor();
+      portal.onmessage = messageHandler;
+      document.body.appendChild(portal);
+    }
+  </script>
+</body>
diff --git a/portals/resources/focus-page-with-button.html b/portals/resources/focus-page-with-button.html
@@ -7,6 +7,12 @@
         button.onfocus = () => e.source.postMessage({focused: true}, {targetOrigin: "*"});
         button.focus();
       }
+
+      if (e.data == "focus-update-active-element") {
+        let button = document.querySelector("button");
+        button.focus();
+        e.source.postMessage({activeElementUpdated: document.activeElement === button}, {targetOrigin: "*"});
+      }
     }
 
     if (window.portalHost)

diff --git a/portals/resources/focus-page-with-x-origin-iframe.sub.html b/portals/resources/focus-page-with-x-origin-iframe.sub.html
@@ -1,10 +1,10 @@
 <!DOCTYPE html>
 <body>
   <script>
-    function handleMessage(e) {
-      if (e.data == "focus") {
+    async function handleMessage(e) {
+      if (e.data == "focus" || e.data == "focus-update-active-element") {
         let iframe = document.querySelector("iframe");
-        iframe.contentWindow.postMessage("focus", "*");
+        iframe.contentWindow.postMessage(e.data, "*");
       }
     }