Don't allow elevation for CHROME_OS.

chrome/browser/resources/options/options.js

Index: chrome/browser/resources/options/options.js
diff --git a/chrome/browser/resources/options/options.js b/chrome/browser/resources/options/options.js
index d62526bed08617d930629dcf8cc9ec88c467fb03..599b07c1df8a9c7a80a590a2bd707e508f008325 100644
--- a/chrome/browser/resources/options/options.js
+++ b/chrome/browser/resources/options/options.js
@@ -149,9 +149,11 @@ function load() {
   if (loadTimeData.getBoolean('managedUsersEnabled')) {
     OptionsPage.registerOverlay(ManagedUserSettingsExceptionsArea.getInstance(),
                                 ManagedUserSettings.getInstance());
-    OptionsPage.registerOverlay(ManagedUserSetPassphraseOverlay.getInstance(),
-                                ManagedUserSettings.getInstance(),
-                                [$('set-passphrase')]);
+    if (!cr.isChromeOS) {
+      OptionsPage.registerOverlay(ManagedUserSetPassphraseOverlay.getInstance(),
+                                  ManagedUserSettings.getInstance(),
+                                  [$('set-passphrase')]);
+    }
     OptionsPage.registerOverlay(ManagedUserSettings.getInstance(),
                                 BrowserOptions.getInstance(),
                                 [$('managed-user-settings-button')]);