[cros] Add --stub-cros-settings option for testing.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index c99c1a6d30406ba1273f1f12cca322caddeb9d0b..b5095dc8f16fc9b5b62ef2cfc9bcd2cb2fc0176b 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -1200,6 +1200,11 @@ const char kGuestSession[]                  = "bwsi";
 // This is typically used to test the chromeos build of chrome on the desktop.
 const char kStubCros[]                      = "stub-cros";
 
+// Indicates that a stub implementation of CrosSettings that stores settings in
+// memory without signing should be used, treating current user as the owner.
+// This option is for testing the chromeos build of chrome on the desktop only.
+const char kStubCrosSettings[]              = "stub-cros-settings";
+
 // URL of the html page for Screen Saver.
 const char kScreenSaverUrl[]                = "screen-saver-url";