Bug 1363505 - Add tab switch reflow test. r?florian
MozReview-Commit-ID: 9A77Fi6Kroi
--- a/browser/base/content/test/performance/browser.ini
+++ b/browser/base/content/test/performance/browser.ini
@@ -1,11 +1,12 @@
[DEFAULT]
support-files =
head.js
[browser_startup.js]
[browser_tabclose_grow_reflows.js]
[browser_tabclose_reflows.js]
[browser_tabopen_reflows.js]
[browser_tabopen_squeeze_reflows.js]
+[browser_tabswitch_reflows.js]
[browser_toolbariconcolor_restyles.js]
[browser_windowclose_reflows.js]
[browser_windowopen_reflows.js]
new file mode 100644
--- /dev/null
+++ b/browser/base/content/test/performance/browser_tabswitch_reflows.js
@@ -0,0 +1,55 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * WHOA THERE: We should never be adding new things to EXPECTED_REFLOWS. This
+ * is a whitelist that should slowly go away as we improve the performance of
+ * the front-end. Instead of adding more reflows to the whitelist, you should
+ * be modifying your code to avoid the reflow.
+ *
+ * See https://developer.mozilla.org/en-US/Firefox/Performance_best_practices_for_Firefox_fe_engineers
+ * for tips on how to do that.
+ */
+const EXPECTED_REFLOWS = [
+ [
+ "_adjustFocusAfterTabSwitch@chrome://browser/content/tabbrowser.xml",
+ ],
+];
+
+if (gMultiProcessBrowser) {
+ EXPECTED_REFLOWS.push(
+ [
+ "_adjustFocusAfterTabSwitch@chrome://browser/content/tabbrowser.xml",
+ ]
+ );
+}
+
+/*
+ * This test ensures that there are no unexpected
+ * uninterruptible reflows when switching between two
+ * tabs that are both fully visible.
+ */
+add_task(async function() {
+ await ensureNoPreloadedBrowser();
+
+ // Because the tab strip is a scrollable frame, we can't use the
+ // default dirtying function from withReflowObserver and reliably
+ // get reflows for the strip. Instead, we provide a node that's
+ // already in the scrollable frame to dirty - in this case, the
+ // original tab.
+ let origTab = gBrowser.selectedTab;
+
+ let firstSwitchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
+ let otherTab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
+ await firstSwitchDone;
+
+ await withReflowObserver(async function() {
+ let switchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
+ gBrowser.selectedTab = origTab;
+ await switchDone;
+ }, EXPECTED_REFLOWS, window, origTab);
+
+ await BrowserTestUtils.removeTab(otherTab);
+});