Revert "Bug 1944147 - Option to turn off newtab for automated tests and other automation. r=mconley" for causing bc failures on browser_preloading_tab_moving.js

This reverts commit 00d4986.

Author: chorotan

browser/modules/AboutNewTab.sys.mjs

@@ -21,7 +21,6 @@ const PREF_ACTIVITY_STREAM_DEBUG = "browser.newtabpage.activity-stream.debug";
 // AboutHomeStartupCache needs us in "quit-application", so stay alive longer.
 // TODO: We could better have a shared async shutdown blocker?
 const TOPIC_APP_QUIT = "profile-before-change";
-const PREF_SHOULD_INITIALIZE = "browser.newtabpage.shouldInitialize";
 
 export const AboutNewTab = {
   QueryInterface: ChromeUtils.generateQI([
@@ -51,16 +50,6 @@ export const AboutNewTab = {
       return;
     }
 
-    // For tests/automation: when false, newtab won't initialize in this session.
-    // Flipping after initialization has no effect on the current session.
-    const shouldInitialize = Services.prefs.getBoolPref(
-      PREF_SHOULD_INITIALIZE,
-      true
-    );
-    if (!shouldInitialize) {
-      return;
-    }
-
     Services.obs.addObserver(this, TOPIC_APP_QUIT);
     if (!AppConstants.RELEASE_OR_BETA) {
       XPCOMUtils.defineLazyPreferenceGetter(
@@ -249,16 +238,11 @@ export const AboutNewTab = {
       this.activityStream.uninit();
       this.activityStream = null;
     }
-    try {
-      Services.obs.removeObserver(this, TOPIC_APP_QUIT);
-      Services.obs.removeObserver(
-        this,
-        lazy.TelemetryReportingPolicy.TELEMETRY_TOU_ACCEPTED_OR_INELIGIBLE
-      );
-    } catch (e) {
-      // If init failed before registering these observers, removeObserver may throw.
-      // Safe to ignore during shutdown.
-    }
+    Services.obs.removeObserver(this, TOPIC_APP_QUIT);
+    Services.obs.removeObserver(
+      this,
+      lazy.TelemetryReportingPolicy.TELEMETRY_TOU_ACCEPTED_OR_INELIGIBLE
+    );
 
     this.initialized = false;
   },

browser/modules/test/browser/browser.toml

@@ -77,8 +77,6 @@ https_first_disabled = true
 ["browser_UsageTelemetry_uniqueOriginsVisitedInPast24Hours.js"]
 https_first_disabled = true
 
-["browser_aboutnewtab_init_gate.js"]
-
 ["browser_preloading_tab_moving.js"]
 
 ["browser_taskbar_preview.js"]