1 files changed, 127 insertions, 0 deletions
diff --git a/dom/base/test/fullscreen/browser_fullscreen-bug-1798219.js b/dom/base/test/fullscreen/browser_fullscreen-bug-1798219.js
new file mode 100644
index 0000000000..2aef23b042
--- /dev/null
+++ b/dom/base/test/fullscreen/browser_fullscreen-bug-1798219.js
@@ -0,0 +1,127 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Import helpers
+/* import-globals-from fullscreen_helpers.js */
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/dom/base/test/fullscreen/fullscreen_helpers.js",
+  this
+);
+
+// This test tends to trigger a race in the fullscreen time telemetry,
+// where the fullscreen enter and fullscreen exit events (which use the
+// same histogram ID) overlap. That causes TelemetryStopwatch to log an
+// error, https://bugzilla.mozilla.org/show_bug.cgi?id=1742890.
+SimpleTest.ignoreAllUncaughtExceptions(true);
+
+add_setup(async function () {
+  await pushPrefs(
+    ["full-screen-api.transition-duration.enter", "0 0"],
+    ["full-screen-api.transition-duration.leave", "0 0"],
+    ["full-screen-api.allow-trusted-requests-only", false]
+  );
+});
+
+async function waitAndCheckFullscreenState(aWindow) {
+  // Wait fullscreen exit event if browser is still in fullscreen mode.
+  if (
+    aWindow.fullScreen ||
+    aWindow.document.documentElement.hasAttribute("inFullscreen")
+  ) {
+    info("The widget is still in fullscreen, wait again");
+    await waitWidgetFullscreenEvent(aWindow, false, true);
+  }
+  if (aWindow.document.documentElement.hasAttribute("inDOMFullscreen")) {
+    info("The chrome document is still in fullscreen, wait again");
+    await waitForFullScreenObserver(aWindow, false, true);
+  }
+
+  // Ensure the browser exits fullscreen state.
+  ok(!aWindow.fullScreen, "The widget should not be in fullscreen");
+  ok(
+    !aWindow.document.documentElement.hasAttribute("inFullscreen"),
+    "The chrome window should not be in fullscreen"
+  );
+  ok(
+    !aWindow.document.documentElement.hasAttribute("inDOMFullscreen"),
+    "The chrome document should not be in fullscreen"
+  );
+}
+
+add_task(async () => {
+  const URL =
+    "http://mochi.test:8888/browser/dom/base/test/fullscreen/file_fullscreen-bug-1798219.html";
+  // We need this dummy tab which load the same URL as test tab to keep the
+  // original content process alive after test page navigates away.
+  let dummyTab = await BrowserTestUtils.openNewForegroundTab(gBrowser, URL);
+
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: URL,
+    },
+    async function (browser) {
+      await SpecialPowers.spawn(browser, [], function () {
+        content.document.querySelector("button").click();
+      });
+
+      // Test requests fullscreen and performs navigation simultaneously,
+      // the fullscreen request might be rejected directly if navigation happens
+      // first, so there might be no reliable state that we can wait. So give
+      // some time for possible fullscreen transition instead and ensure window
+      // should end up exiting fullscreen.
+      await new Promise(aResolve => {
+        SimpleTest.executeSoon(() => {
+          SimpleTest.executeSoon(aResolve);
+        });
+      });
+      await waitAndCheckFullscreenState(window);
+    }
+  );
+
+  let dummyTabClosed = BrowserTestUtils.waitForTabClosing(dummyTab);
+  BrowserTestUtils.removeTab(dummyTab);
+  await dummyTabClosed;
+});
+
+add_task(async () => {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://mochi.test:8888/browser/dom/base/test/fullscreen/file_fullscreen-bug-1798219-2.html",
+    },
+    async function (browser) {
+      // Open a new window to run the tests, the original window will keep the
+      // original content process alive after the test window navigates away.
+      let promiseWin = BrowserTestUtils.waitForNewWindow();
+      await SpecialPowers.spawn(browser, [], function () {
+        content.document.querySelector("button").click();
+      });
+      let newWindow = await promiseWin;
+
+      await SpecialPowers.spawn(
+        newWindow.gBrowser.selectedTab.linkedBrowser,
+        [],
+        function () {
+          content.document.querySelector("button").click();
+        }
+      );
+
+      // Test requests fullscreen and performs navigation simultaneously,
+      // the fullscreen request might be rejected directly if navigation happens
+      // first, so there might be no reliable state that we can wait. So give
+      // some time for possible fullscreen transition instead and ensure window
+      // should end up exiting fullscreen.
+      await new Promise(aResolve => {
+        SimpleTest.executeSoon(() => {
+          SimpleTest.executeSoon(aResolve);
+        });
+      });
+      await waitAndCheckFullscreenState(newWindow);
+
+      newWindow.close();
+    }
+  );
+});