[cros] Add support for transparent background in sign in screen.

chrome/browser/ui/webui/chromeos/login/oobe_ui.cc

Index: chrome/browser/ui/webui/chromeos/login/oobe_ui.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/oobe_ui.cc b/chrome/browser/ui/webui/chromeos/login/oobe_ui.cc
index 0b36cd97460192005414e678fc04abf01408061b..aa11ab9544ffbcc033015fe4ca31cbab4a59cf7e 100644
--- a/chrome/browser/ui/webui/chromeos/login/oobe_ui.cc
+++ b/chrome/browser/ui/webui/chromeos/login/oobe_ui.cc
@@ -30,6 +30,7 @@
 #include "chrome/browser/ui/webui/chromeos/login/user_image_screen_handler.h"
 #include "chrome/browser/ui/webui/options2/chromeos/user_image_source2.h"
 #include "chrome/browser/ui/webui/theme_source.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/web_contents.h"
@@ -227,6 +228,11 @@ void OobeUI::GetLocalizedStrings(base::DictionaryValue* localized_strings) {
   for (size_t i = 0; i < handlers_.size(); ++i)
     handlers_[i]->GetLocalizedStrings(localized_strings);
   ChromeURLDataManager::DataSource::SetFontAndTextDirection(localized_strings);
+
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableNewOobe))
+    localized_strings->SetString("oobeType", "new");
+  else
+    localized_strings->SetString("oobeType", "old");
 }
 
 void OobeUI::AddScreenHandler(BaseScreenHandler* handler) {