1 files changed, 69 insertions, 0 deletions
diff --git a/browser/base/content/test/performance/browser_panel_vsync.js b/browser/base/content/test/performance/browser_panel_vsync.js
new file mode 100644
index 0000000000..73c56b9095
--- /dev/null
+++ b/browser/base/content/test/performance/browser_panel_vsync.js
@@ -0,0 +1,69 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/browser/components/downloads/test/browser/head.js",
+  this
+);
+
+add_task(
+  async function test_opening_panel_and_closing_should_not_leave_vsync() {
+    await SpecialPowers.pushPrefEnv({
+      set: [["browser.download.autohideButton", false]],
+    });
+    await promiseButtonShown("downloads-button");
+
+    const downloadsButton = document.getElementById("downloads-button");
+    const shownPromise = promisePanelOpened();
+    EventUtils.synthesizeNativeMouseEvent({
+      type: "click",
+      target: downloadsButton,
+      atCenter: true,
+    });
+    await shownPromise;
+
+    is(DownloadsPanel.panel.state, "open", "Check that panel state is 'open'");
+
+    await TestUtils.waitForCondition(
+      () => !ChromeUtils.vsyncEnabled(),
+      "Make sure vsync disabled"
+    );
+    // Should not already be using vsync
+    ok(!ChromeUtils.vsyncEnabled(), "vsync should be off initially");
+
+    if (
+      AppConstants.platform == "linux" &&
+      DownloadsPanel.panel.state != "open"
+    ) {
+      // Panels sometime receive spurious popuphiding events on Linux.
+      // Given the main target of this test is Windows, avoid causing
+      // intermittent failures and just make the test return early.
+      todo(
+        false,
+        "panel should still be 'open', current state: " +
+          DownloadsPanel.panel.state
+      );
+      return;
+    }
+
+    const hiddenPromise = BrowserTestUtils.waitForEvent(
+      DownloadsPanel.panel,
+      "popuphidden"
+    );
+    EventUtils.synthesizeKey("VK_ESCAPE", {}, window);
+    await hiddenPromise;
+    await TestUtils.waitForCondition(
+      () => !ChromeUtils.vsyncEnabled(),
+      "wait for vsync to be disabled again"
+    );
+
+    ok(!ChromeUtils.vsyncEnabled(), "vsync should still be off");
+    is(
+      DownloadsPanel.panel.state,
+      "closed",
+      "Check that panel state is 'closed'"
+    );
+  }
+);