feat(firefox): support running beforeunload hooks when closing (#4003)

experimental/puppeteer-firefox/lib/Page.js

@@ -549,8 +549,11 @@ class Page extends EventEmitter {
     return await this._frameManager.mainFrame().select(selector, ...values);
   }
 
-  async close() {
-    await this._session.send('Browser.closePage' );
+  async close(options = {}) {
+    const {
+      runBeforeUnload = false,
+    } = options;
+    await this._session.send('Browser.closePage', { runBeforeUnload });
   }
 
   async content() {

experimental/puppeteer-firefox/misc/puppeteer.cfg

@@ -104,7 +104,7 @@ pref("datareporting.policy.dataSubmissionPolicyAccepted", false);
 pref("datareporting.policy.dataSubmissionPolicyBypassNotification", true);
 
 // Automatically unload beforeunload alerts
-pref("dom.disable_beforeunload", true);
+pref("dom.disable_beforeunload", false);
 
 // Disable popup-blocker
 pref("dom.disable_open_during_load", false);

experimental/puppeteer-firefox/package.json

@@ -9,7 +9,7 @@
     "node": ">=8.9.4"
   },
   "puppeteer": {
-    "firefox_revision": "0647e24cc0b90c07c8ddb32e63ce333839329527"
+    "firefox_revision": "4ba5b441257d5938d032d09fc09e45ea9d8f2e3a"
   },
   "scripts": {
     "install": "node install.js",

test/assets/beforeunload.html

@@ -1,5 +1,10 @@
+<div>beforeunload demo.</div>
 <script>
 window.addEventListener('beforeunload', event => {
+  // Chrome way.
   event.returnValue = 'Leave?';
+  // Firefox way.
+  event.preventDefault();
 });
 </script>
+

test/page.spec.js

@@ -48,19 +48,30 @@ module.exports.addTests = function({testRunner, expect, headless, Errors, Device
       await newPage.close();
       expect(await browser.pages()).not.toContain(newPage);
     });
-    it_fails_ffox('should run beforeunload if asked for', async({context, server}) => {
+    it('should run beforeunload if asked for', async({context, server}) => {
       const newPage = await context.newPage();
       await newPage.goto(server.PREFIX + '/beforeunload.html');
       // We have to interact with a page so that 'beforeunload' handlers
       // fire.
       await newPage.click('body');
-      newPage.close({ runBeforeUnload: true });
+      const pageClosingPromise = newPage.close({ runBeforeUnload: true });
       const dialog = await waitEvent(newPage, 'dialog');
       expect(dialog.type()).toBe('beforeunload');
       expect(dialog.defaultValue()).toBe('');
-      expect(dialog.message()).toBe('');
-      dialog.accept();
-      await waitEvent(newPage, 'close');
+      if (CHROME)
+        expect(dialog.message()).toBe('');
+      else
+        expect(dialog.message()).toBe('This page is asking you to confirm that you want to leave - data you have entered may not be saved.');
+      await dialog.accept();
+      await pageClosingPromise;
+    });
+    it('should *not* run beforeunload by default', async({context, server}) => {
+      const newPage = await context.newPage();
+      await newPage.goto(server.PREFIX + '/beforeunload.html');
+      // We have to interact with a page so that 'beforeunload' handlers
+      // fire.
+      await newPage.click('body');
+      await newPage.close();
     });
     it('should set the page close state', async({context}) => {
       const newPage = await context.newPage();