Migrate chrome/browser/ash/* to namespace ash (3/3)

This CL migrates top-level files from chrome/browser/ash/ to namespace
ash.

This CL is part of the Chrome OS source code directory migration:
https://docs.google.com/document/d/1g-98HpzA8XcoGBWUv1gQNr4rbnD5yfvbtYZyPDDbkaE.

Bug: 1164001
Change-Id: I224c05cfb21e2acca611066c058fa5dde01c4f45
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3231177
Commit-Queue: Henrique Ferreiro <[email protected]>
Reviewed-by: Hidehiko Abe <[email protected]>
Owners-Override: Hidehiko Abe <[email protected]>
Cr-Commit-Position: refs/heads/main@{#940263}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index eefd6cf..9309b08 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -1042,9 +1042,9 @@
       registry);
   ash::power::auto_screen_brightness::MetricsReporter::RegisterLocalStatePrefs(
       registry);
-  chromeos::Preferences::RegisterPrefs(registry);
+  ash::Preferences::RegisterPrefs(registry);
   ash::ResetScreen::RegisterPrefs(registry);
-  chromeos::SchedulerConfigurationManager::RegisterLocalStatePrefs(registry);
+  ash::SchedulerConfigurationManager::RegisterLocalStatePrefs(registry);
   ash::ServicesCustomizationDocument::RegisterPrefs(registry);
   chromeos::SigninScreenHandler::RegisterPrefs(registry);
   ash::StartupUtils::RegisterPrefs(registry);
@@ -1359,7 +1359,7 @@
   ash::HelpAppNotificationController::RegisterProfilePrefs(registry);
   ash::quick_unlock::FingerprintStorage::RegisterProfilePrefs(registry);
   ash::quick_unlock::PinStoragePrefs::RegisterProfilePrefs(registry);
-  chromeos::Preferences::RegisterProfilePrefs(registry);
+  ash::Preferences::RegisterProfilePrefs(registry);
   ash::EnterprisePrintersProvider::RegisterProfilePrefs(registry);
   ash::parent_access::ParentAccessService::RegisterProfilePrefs(registry);
   ash::quick_answers::prefs::RegisterProfilePrefs(registry);