diff --git components/prefs/pref_service.h components/prefs/pref_service.h
index f1856d6ee4419..413b77e80d84d 100644
--- components/prefs/pref_service.h
+++ components/prefs/pref_service.h
@@ -52,6 +52,10 @@ namespace base {
 class FilePath;
 }
 
+namespace pref_helper {
+class Registrar;
+}
+
 namespace prefs {
 class ScopedDictionaryPrefUpdate;
 }
@@ -441,6 +445,8 @@ class COMPONENTS_PREFS_EXPORT PrefService {
   // declared as a friend, too.
   friend class PrefChangeRegistrar;
   friend class subtle::PrefMemberBase;
+  // CEF registration manager.
+  friend class pref_helper::Registrar;
 
   // These are protected so they can only be accessed by the friend
   // classes listed above.
diff --git components/variations/synthetic_trials_active_group_id_provider.cc components/variations/synthetic_trials_active_group_id_provider.cc
index bd51697297471..3e669cd080457 100644
--- components/variations/synthetic_trials_active_group_id_provider.cc
+++ components/variations/synthetic_trials_active_group_id_provider.cc
@@ -27,7 +27,7 @@ SyntheticTrialsActiveGroupIdProvider::GetActiveGroupIds() {
   return group_ids_;
 }
 
-#if !defined(NDEBUG)
+#if !defined(NDEBUG) || BUILDFLAG(ENABLE_CEF)
 std::vector<SyntheticTrialGroup>
 SyntheticTrialsActiveGroupIdProvider::GetGroups() {
   base::AutoLock scoped_lock(lock_);
@@ -38,7 +38,7 @@ SyntheticTrialsActiveGroupIdProvider::GetGroups() {
 void SyntheticTrialsActiveGroupIdProvider::ResetForTesting() {
   base::AutoLock scoped_lock(lock_);
   group_ids_.clear();
-#if !defined(NDEBUG)
+#if !defined(NDEBUG) || BUILDFLAG(ENABLE_CEF)
   groups_.clear();
 #endif  // !defined(NDEBUG)
 }
@@ -53,7 +53,7 @@ void SyntheticTrialsActiveGroupIdProvider::OnSyntheticTrialsChanged(
     for (const auto& group : groups) {
       group_ids_.push_back(group.id());
     }
-#if !defined(NDEBUG)
+#if !defined(NDEBUG) || BUILDFLAG(ENABLE_CEF)
     groups_ = groups;
 #endif  // !defined(NDEBUG)
   }
diff --git components/variations/synthetic_trials_active_group_id_provider.h components/variations/synthetic_trials_active_group_id_provider.h
index b4a999731d996..0bbac173fddf1 100644
--- components/variations/synthetic_trials_active_group_id_provider.h
+++ components/variations/synthetic_trials_active_group_id_provider.h
@@ -10,6 +10,7 @@
 #include "base/component_export.h"
 #include "base/synchronization/lock.h"
 #include "base/thread_annotations.h"
+#include "cef/libcef/features/features.h"
 #include "components/variations/active_field_trials.h"
 #include "components/variations/synthetic_trials.h"
 
@@ -36,7 +37,7 @@ class COMPONENT_EXPORT(VARIATIONS) SyntheticTrialsActiveGroupIdProvider
   // Returns currently active synthetic trial group IDs.
   std::vector<ActiveGroupId> GetActiveGroupIds();
 
-#if !defined(NDEBUG)
+#if !defined(NDEBUG) || BUILDFLAG(ENABLE_CEF)
   // In debug mode, not only the group IDs are tracked but also the full group
   // info, to display the names unhashed in chrome://version.
   std::vector<SyntheticTrialGroup> GetGroups();
@@ -60,7 +61,7 @@ class COMPONENT_EXPORT(VARIATIONS) SyntheticTrialsActiveGroupIdProvider
 
   base::Lock lock_;
   std::vector<ActiveGroupId> group_ids_;  // GUARDED_BY(lock_);
-#if !defined(NDEBUG)
+#if !defined(NDEBUG) || BUILDFLAG(ENABLE_CEF)
   // In debug builds, keep the full group information to be able to display it
   // in chrome://version.
   std::vector<SyntheticTrialGroup> groups_;  // GUARDED_BY(lock_);