1 files changed, 122 insertions, 0 deletions
diff --git a/dom/base/test/fullscreen/browser_fullscreen-document-mutation-race.js b/dom/base/test/fullscreen/browser_fullscreen-document-mutation-race.js
new file mode 100644
index 0000000000..75ca199aaa
--- /dev/null
+++ b/dom/base/test/fullscreen/browser_fullscreen-document-mutation-race.js
@@ -0,0 +1,122 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+requestLongerTimeout(2);
+
+// Import helpers
+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.
+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 startTests(setupFun, name) {
+  TEST_URLS.forEach(url => {
+    add_task(async () => {
+      info(`Test ${name}, url: ${url}`);
+      await BrowserTestUtils.withNewTab(
+        {
+          gBrowser,
+          url,
+        },
+        async function (browser) {
+          let promiseFsState = Promise.all([
+            setupFun(browser),
+            waitForFullscreenState(document, false, true),
+          ]);
+          // Trigger click event in inner most iframe
+          SpecialPowers.spawn(
+            browser.browsingContext.children[0].children[0],
+            [],
+            function () {
+              content.setTimeout(() => {
+                content.document.getElementById("div").click();
+              }, 0);
+            }
+          );
+          await promiseFsState;
+
+          // Ensure the browser exits fullscreen state.
+          ok(
+            !window.fullScreen,
+            "The chrome window should not be in fullscreen"
+          );
+          ok(
+            !document.documentElement.hasAttribute("inDOMFullscreen"),
+            "The chrome document should not be in fullscreen"
+          );
+        }
+      );
+    });
+  });
+}
+
+function RemoveElementFromRemoteDocument(aBrowsingContext, aElementId) {
+  return SpecialPowers.spawn(
+    aBrowsingContext,
+    [aElementId],
+    async function (id) {
+      content.document.addEventListener(
+        "fullscreenchange",
+        function () {
+          content.document.getElementById(id).remove();
+        },
+        { once: true }
+      );
+    }
+  );
+}
+
+startTests(async browser => {
+  // toplevel
+  let promise = waitRemoteFullscreenExitEvents([
+    // browsingContext, name
+    [browser.browsingContext, "toplevel"],
+  ]);
+  await RemoveElementFromRemoteDocument(browser.browsingContext, "div");
+  return promise;
+}, "document_mutation_toplevel");
+
+startTests(async browser => {
+  // middle iframe
+  let promise = waitRemoteFullscreenExitEvents([
+    // browsingContext, name
+    [browser.browsingContext, "toplevel"],
+    [browser.browsingContext.children[0], "middle"],
+  ]);
+  await RemoveElementFromRemoteDocument(
+    browser.browsingContext.children[0],
+    "div"
+  );
+  return promise;
+}, "document_mutation_middle_frame");
+
+startTests(async browser => {
+  // innermost iframe
+  let promise = waitRemoteFullscreenExitEvents([
+    // browsingContext, name
+    [browser.browsingContext, "toplevel"],
+    [browser.browsingContext.children[0], "middle"],
+    [browser.browsingContext.children[0].children[0], "inner"],
+  ]);
+  await RemoveElementFromRemoteDocument(
+    browser.browsingContext.children[0].children[0],
+    "div"
+  );
+  return promise;
+}, "document_mutation_inner_frame");