cros: Break BaseScreenHandler into two classes.

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
index 57d1043dbc393cf0e21ce6c5004b0dc2e4360c17..68d5032d29f0643dd6efc6b457a62c4cbd872ec2 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
@@ -21,7 +21,7 @@
 #include "chrome/browser/chromeos/login/signin_specifics.h"
 #include "chrome/browser/chromeos/login/ui/login_display.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
-#include "chrome/browser/ui/webui/chromeos/login/base_screen_handler.h"
+#include "chrome/browser/ui/webui/chromeos/login/base_webui_handler.h"
 #include "chrome/browser/ui/webui/chromeos/login/network_state_informer.h"
 #include "chrome/browser/ui/webui/chromeos/login/oobe_ui.h"
 #include "chromeos/dbus/power_manager_client.h"
@@ -218,7 +218,7 @@ class SigninScreenHandlerDelegate {
 // A class that handles the WebUI hooks in sign-in screen in OobeUI and
 // LoginDisplay.
 class SigninScreenHandler
-    : public BaseScreenHandler,
+    : public BaseWebUIHandler,
       public LoginDisplayWebUIHandler,
       public content::NotificationObserver,
       public NetworkStateInformer::NetworkStateInformerObserver,