[FIX] events: correctly call handlers in iframes

Previously, event handlers would not work when an app was mounted in an
iframe, this is caused by a guard in the event handler that checks that
the target element is still in the document, but it doesn't check
against the correct document in the case of an iframe.

This commit changes the check to check against the target's
ownerDocument.

src/runtime/blockdom/events.ts

@@ -27,8 +27,8 @@ function createElementHandler(evName: string, capture: boolean = false): EventHa
   }
 
   function listener(ev: Event) {
-    const currentTarget = ev.currentTarget;
+    const currentTarget = ev.currentTarget as HTMLElement;
-    if (!currentTarget || !document.contains(currentTarget as HTMLElement)) return;
+    if (!currentTarget || !currentTarget.ownerDocument.contains(currentTarget)) return;
     const data = (currentTarget as any)[eventKey];
     if (!data) return;
     config.mainEventHandler(data, ev, currentTarget);

tests/components/__snapshots__/event_handling.test.ts.snap

@@ -58,6 +58,20 @@ exports[`event handling handler receive the event as argument 2`] = `
 }"
 `;
 
+exports[`event handling handler works when app is mounted in an iframe 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<span block-handler-0=\\"click\\">click me</span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let hdlr1 = [ctx['inc'], ctx];
+    return block1([hdlr1]);
+  }
+}"
+`;
+
 exports[`event handling input blur event is not called if component is destroyed 1`] = `
 "function anonymous(app, bdom, helpers
 ) {

tests/components/event_handling.test.ts

@@ -171,4 +171,22 @@ describe("event handling", () => {
     // input is removed when component is destroyed => nothing should happen
     expect([]).toBeLogged();
   });
+
+  test("handler works when app is mounted in an iframe", async () => {
+    let clickCount = 0;
+
+    class Parent extends Component {
+      static template = xml`<span t-on-click="inc">click me</span>`;
+      inc() {
+        clickCount++;
+      }
+    }
+    const iframe = document.createElement("iframe");
+    fixture.appendChild(iframe);
+    const iframeDoc = iframe.contentDocument!;
+    await mount(Parent, iframeDoc.body);
+    expect(clickCount).toBe(0);
+    iframeDoc.querySelector("span")!.click();
+    expect(clickCount).toBe(1);
+  });
 });