1 files changed, 31 insertions, 0 deletions
diff --git a/dom/ipc/tests/browser_layers_unloaded_while_interruptingJS.js b/dom/ipc/tests/browser_layers_unloaded_while_interruptingJS.js
new file mode 100644
index 0000000000..be176dd101
--- /dev/null
+++ b/dom/ipc/tests/browser_layers_unloaded_while_interruptingJS.js
@@ -0,0 +1,31 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function test_check_layers_cleared() {
+  let initialTab = gBrowser.selectedTab;
+  await BrowserTestUtils.withNewTab("about:blank", async browser => {
+    await ContentTask.spawn(browser, null, () => {
+      return new Promise(resolve => {
+        content.requestAnimationFrame(() => {
+          content.setTimeout(
+            "let start = performance.now(); while (performance.now() < start + 5000);"
+          );
+          resolve();
+        });
+      });
+    });
+    let layersCleared = BrowserTestUtils.waitForEvent(
+      window,
+      "MozLayerTreeCleared"
+    );
+    let startWaiting = performance.now();
+    await BrowserTestUtils.switchTab(gBrowser, initialTab);
+    await layersCleared;
+    ok(
+      performance.now() < startWaiting + 2000,
+      "MozLayerTreeCleared should be dispatched while the script is still running"
+    );
+  });
+});