Make customization documents singletons.

chrome/browser/chromeos/login/existing_user_controller.h

Index: chrome/browser/chromeos/login/existing_user_controller.h
diff --git a/chrome/browser/chromeos/login/existing_user_controller.h b/chrome/browser/chromeos/login/existing_user_controller.h
index f01b422a2a906c0a11f8b95cd8a568b0350ae995..57193981e3ef91e32adc0ad964c28ccde3ea4a25 100644
--- a/chrome/browser/chromeos/login/existing_user_controller.h
+++ b/chrome/browser/chromeos/login/existing_user_controller.h
@@ -55,10 +55,6 @@ class ExistingUserController : public LoginDisplay::Delegate,
     return current_controller_;
   }
 
-  void set_initial_start_page(const std::string& url) {
-    initial_start_page_ = url;
-  }
-
   // Creates and shows login UI for known users.
   void Init(const UserVector& users);
 
@@ -159,9 +155,6 @@ class ExistingUserController : public LoginDisplay::Delegate,
   // URL to append to start Guest mode with.
   GURL guest_mode_url_;
 
-  // URL to open on first owner login from OEM customization manifest.
-  std::string initial_start_page_;
-
   // Used for user image changed notifications.
   NotificationRegistrar registrar_;