Guard Child Account Status with contraction directives (ifdef).

This way it's clear at callsite that the setting is only read and
written by a specific platform (ChromeOS).

Bug: 402135565
Change-Id: I33e926a462a31e70455a1f867e51152bbceabb6f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6382899
Reviewed-by: Anthi Orfanou <[email protected]>
Reviewed-by: David Trainor <[email protected]>
Commit-Queue: Tomek Jurkiewicz <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1437092}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index fc3e3f7..98807c4d 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -176,6 +176,7 @@
 #include "components/subresource_filter/content/shared/browser/ruleset_service.h"
 #include "components/subresource_filter/core/common/constants.h"
 #include "components/supervised_user/core/browser/supervised_user_preferences.h"
+#include "components/supervised_user/core/common/pref_names.h"
 #include "components/sync/base/pref_names.h"
 #include "components/sync/service/glue/sync_transport_data_prefs.h"
 #include "components/sync/service/sync_prefs.h"
@@ -2756,6 +2757,11 @@
   // Added 03/2025.
   profile_prefs->ClearPref(kPasswordChangeFlowNoticeAgreement);
 
+#if !BUILDFLAG(IS_CHROMEOS)
+  // Added 03/2025.
+  profile_prefs->ClearPref(prefs::kChildAccountStatusKnown);
+#endif
+
   // Please don't delete the following line. It is used by PRESUBMIT.py.
   // END_MIGRATE_OBSOLETE_PROFILE_PREFS