Bug 1890076 - Make browser.startup.record and browser.startup.recordImage static prefs. r=florian

Differential Revision: https://phabricator.services.mozilla.com/D206830

browser/base/content/test/performance/browser_preferences_usage.js

@@ -70,13 +70,6 @@ function checkPrefGetters(stats, max, knownProblematicPrefs = {}) {
     }
   }
 
-  // This pref will be accessed by mozJSComponentLoader when loading modules,
-  // which fails TV runs since they run the test multiple times without restarting.
-  // We just ignore this pref, since it's for testing only anyway.
-  if (knownProblematicPrefs["browser.startup.record"]) {
-    delete knownProblematicPrefs["browser.startup.record"];
-  }
-
   let unusedPrefs = Object.keys(knownProblematicPrefs);
   is(
     unusedPrefs.length,
@@ -104,18 +97,9 @@ add_task(async function startup() {
   let max = 40;
 
   let knownProblematicPrefs = {
-    "browser.startup.record": {
-      // This pref is accessed in Nighly and debug builds only.
-      min: 200,
-      max: 450,
-    },
     "network.loadinfo.skip_type_assertion": {
       // This is accessed in debug only.
     },
-    "chrome.override_package.global": {
-      min: 0,
-      max: 50,
-    },
   };
 
   let startupRecorder =
@@ -135,9 +119,6 @@ add_task(async function open_10_tabs() {
   const max = 4 * DEFAULT_PROCESS_COUNT;
 
   let knownProblematicPrefs = {
-    "browser.startup.record": {
-      max: 20,
-    },
     "browser.tabs.remote.logSwitchTiming": {
       max: 35,
     },

browser/components/StartupRecorder.sys.mjs

@@ -6,6 +6,23 @@ const Cm = Components.manager;
 Cm.QueryInterface(Ci.nsIServiceManager);
 
 import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "BROWSER_STARTUP_RECORD",
+  "browser.startup.record",
+  false
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "BROWSER_STARTUP_RECORD_IMAGES",
+  "browser.startup.recordImages",
+  false
+);
 
 let firstPaintNotification = "widget-first-paint";
 // widget-first-paint fires much later than expected on Linux.
@@ -98,10 +115,7 @@ StartupRecorder.prototype = {
         return;
       }
 
-      if (
+      if (!lazy.BROWSER_STARTUP_RECORD && !lazy.BROWSER_STARTUP_RECORD_IMAGES) {
-        !Services.prefs.getBoolPref("browser.startup.record", false) &&
-        !Services.prefs.getBoolPref("browser.startup.recordImages", false)
-      ) {
         this._resolve();
         this._resolve = null;
         return;
@@ -118,7 +132,7 @@ StartupRecorder.prototype = {
         "browser-startup-idle-tasks-finished",
       ];
 
-      if (Services.prefs.getBoolPref("browser.startup.recordImages", false)) {
+      if (lazy.BROWSER_STARTUP_RECORD_IMAGES) {
         // For code simplicify, recording images excludes the other startup
         // recorder behaviors, so we can observe only the image topics.
         topics = [
@@ -180,7 +194,7 @@ StartupRecorder.prototype = {
         this.record.bind(this, "before handling user events")
       );
     } else if (topic == "browser-startup-idle-tasks-finished") {
-      if (Services.prefs.getBoolPref("browser.startup.recordImages", false)) {
+      if (lazy.BROWSER_STARTUP_RECORD_IMAGES) {
         Services.obs.removeObserver(this, "image-drawing");
         Services.obs.removeObserver(this, "image-loading");
         this._resolve();

js/xpconnect/loader/mozJSModuleLoader.cpp

@@ -1505,7 +1505,7 @@ nsresult mozJSModuleLoader::GetLoadedJSAndESModules(
 #ifdef STARTUP_RECORDER_ENABLED
 void mozJSModuleLoader::RecordImportStack(JSContext* aCx,
                                           const nsACString& aLocation) {
-  if (!Preferences::GetBool("browser.startup.record", false)) {
+  if (!StaticPrefs::browser_startup_record()) {
     return;
   }
 
@@ -1515,7 +1515,7 @@ void mozJSModuleLoader::RecordImportStack(JSContext* aCx,
 
 void mozJSModuleLoader::RecordImportStack(
     JSContext* aCx, JS::loader::ModuleLoadRequest* aRequest) {
-  if (!Preferences::GetBool("browser.startup.record", false)) {
+  if (!StaticPrefs::browser_startup_record()) {
     return;
   }
 

modules/libpref/init/StaticPrefList.yaml

@@ -1659,6 +1659,13 @@
   mirror: once
   do_not_use_directly: true
 
+#if defined(NIGHTLY_BUILD) || defined(MOZ_DEV_EDITION) || defined(DEBUG)
+- name: browser.startup.record
+  type: bool
+  value: false
+  mirror: always
+#endif
+
 # Causes SessionStore to ignore non-final update messages from
 # browser tabs that were not caused by a flush from the parent.
 # This is a testing flag and should not be used by end-users.