Adding pref to store the user-selected proximity threshold.

chrome/browser/extensions/api/settings_private/prefs_util.cc

Index: chrome/browser/extensions/api/settings_private/prefs_util.cc
diff --git a/chrome/browser/extensions/api/settings_private/prefs_util.cc b/chrome/browser/extensions/api/settings_private/prefs_util.cc
index a0769f5198b33f2094527144635df95a879dce6c..583d6eb711a108abcdc9c9801bf872b8a60b196b 100644
--- a/chrome/browser/extensions/api/settings_private/prefs_util.cc
+++ b/chrome/browser/extensions/api/settings_private/prefs_util.cc
@@ -18,6 +18,7 @@
 #include "components/drive/drive_pref_names.h"
 #include "components/password_manager/core/common/password_manager_pref_names.h"
 #include "components/prefs/pref_service.h"
+#include "components/proximity_auth/proximity_auth_pref_names.h"
 #include "components/proxy_config/proxy_config_pref_names.h"
 #include "components/safe_browsing/common/safe_browsing_prefs.h"
 #include "components/search_engines/default_search_manager.h"
@@ -226,6 +227,8 @@ const PrefsUtil::TypedPrefMap& PrefsUtil::GetWhitelistedKeys() {
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)[::prefs::kEnableQuickUnlockFingerprint] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
+  (*s_whitelist)[proximity_auth::prefs::kEasyUnlockProximityThreshold] =
+      settings_private::PrefType::PREF_TYPE_NUMBER;
 
   // Accessibility.
   (*s_whitelist)[::prefs::kAccessibilitySpokenFeedbackEnabled] =