fune/browser/base/content/test/performance/browser_windowopen_reflows.js

86 lines
2.9 KiB
JavaScript

/* 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 = [
{
stack: [
"onOverflow@resource:///modules/CustomizableUI.jsm",
"init@resource:///modules/CustomizableUI.jsm",
"observe@resource:///modules/CustomizableUI.jsm",
"_delayedStartup@chrome://browser/content/browser.js",
],
times: 2, // This number should only ever go down - never up.
},
];
if (Services.appinfo.OS == "WINNT") {
EXPECTED_REFLOWS.push(
{
stack: [
"verticalMargins@chrome://browser/content/browser-tabsintitlebar.js",
"_update@chrome://browser/content/browser-tabsintitlebar.js",
"init@chrome://browser/content/browser-tabsintitlebar.js",
"handleEvent@chrome://browser/content/tabbrowser.xml",
],
times: 2, // This number should only ever go down - never up.
},
);
}
if (Services.appinfo.OS == "WINNT" || Services.appinfo.OS == "Darwin") {
EXPECTED_REFLOWS.push(
{
stack: [
"select@chrome://global/content/bindings/textbox.xml",
"focusAndSelectUrlBar@chrome://browser/content/browser.js",
],
},
{
stack: [
"rect@chrome://browser/content/browser-tabsintitlebar.js",
"_update@chrome://browser/content/browser-tabsintitlebar.js",
"init@chrome://browser/content/browser-tabsintitlebar.js",
"handleEvent@chrome://browser/content/tabbrowser.xml",
],
times: 4, // This number should only ever go down - never up.
},
);
}
/*
* This test ensures that there are no unexpected
* uninterruptible reflows when opening new windows.
*/
add_task(async function() {
// Flushing all caches helps to ensure that we get consistent
// behaviour when opening a new window, even if windows have been
// opened in previous tests.
Services.obs.notifyObservers(null, "startupcache-invalidate");
Services.obs.notifyObservers(null, "chrome-flush-skin-caches");
Services.obs.notifyObservers(null, "chrome-flush-caches");
let win = OpenBrowserWindow();
await withReflowObserver(async function() {
let resizeEvent = BrowserTestUtils.waitForEvent(win, "resize");
let delayedStartup =
TestUtils.topicObserved("browser-delayed-startup-finished",
subject => subject == win);
await resizeEvent;
await delayedStartup;
}, EXPECTED_REFLOWS, win);
await BrowserTestUtils.closeWindow(win);
});