Synchronous prevent default (#2792)

* add prevent default methods to the event

* sync prevent default almost working

* sync prevent default working

* Move event handling into the runtime

* update core tests

* restore desktop file dialog

* implement prevent default on web

* add a hint about the new prevent default method

* fix web prevent default

* Fix CTRL+click on links

* fix values memorize in place test

* Fix a few more tests

* Add a playwright test for sync prevent default

* Fix core doc tests

* create a deprecated VirtualDom::handle_event

* fix macos imports in desktop

* Fix onmounted event

* Fix liveview support

* switch to RefCell for metadata

* Remove println

* remove prevent default attribute

* remove web specific link behavior

* Fix liveview links

* more liveview fixes for link

* Fix merge conflicts

* Fix clippy

* use the new prevent default in the file upload example

packages/playwright-tests/web.spec.js

@@ -94,4 +94,16 @@ test("eval", async ({ page }) => {
   await expect(div).toHaveText("returned eval value");
 });
 
-// Shutdown the li
+test("prevent default", async ({ page }) => {
+  await page.goto("http://localhost:9999");
+
+  // Expect the page to contain the div with the eval and have no text.
+  const a = page.locator("a.prevent-default");
+  await expect(a).toHaveText("View source");
+
+  // Click the <a> element to change the text
+  await a.click();
+
+  // Check that the <a> element changed.
+  await expect(a).toHaveText("Psych!");
+});