Move chromeos_switches.* to ash/constants/

This is a precursor CL before migrating //chromeos/constants to //ash.

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

No-Presubmit: true
Bug: 1164001
Change-Id: I0ae4aae094fe2d81de6b5f0df8a2ab33a9f951d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2665733
Auto-Submit: Henrique Ferreiro <[email protected]>
Commit-Queue: James Cook <[email protected]>
Owners-Override: James Cook <[email protected]>
Reviewed-by: James Cook <[email protected]>
Cr-Commit-Position: refs/heads/master@{#851329}
diff --git a/chrome/browser/ui/webui/help/help_utils_chromeos.cc b/chrome/browser/ui/webui/help/help_utils_chromeos.cc
index df7511c1..caefb308 100644
--- a/chrome/browser/ui/webui/help/help_utils_chromeos.cc
+++ b/chrome/browser/ui/webui/help/help_utils_chromeos.cc
@@ -8,10 +8,10 @@
 
 #include <algorithm>
 
+#include "ash/constants/ash_switches.h"
 #include "base/logging.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
-#include "chromeos/constants/chromeos_switches.h"
 #include "chromeos/settings/cros_settings_names.h"
 
 namespace help_utils_chromeos {