cros: Enable WebUILoginView reuse.

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

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <vector>
@@ skipping 882 matching lines @@
   // Forces a reload for Gaia screen on hiding error message.
   if (IsGaiaVisible() || IsGaiaHiddenByError())
     ReloadGaia(reason == NetworkError::ERROR_REASON_NETWORK_STATE_CHANGED);
 }
 
 void SigninScreenHandler::ReloadGaia(bool force_reload) {
   gaia_screen_handler_->ReloadGaia(force_reload);
 }
 
 void SigninScreenHandler::Initialize() {
-  // If delegate_ is nullptr here (e.g. WebUIScreenLocker has been destroyed),
-  // don't do anything, just return.
-  if (!delegate_)
-    return;
-
-  if (show_on_init_) {
+  if (delegate_ && show_on_init_) {
     show_on_init_ = false;
     ShowImpl();
   }
 }
 
 gfx::NativeWindow SigninScreenHandler::GetNativeWindow() {
   if (native_window_delegate_)
     return native_window_delegate_->GetNativeWindow();
   return nullptr;
 }
@@ skipping 619 matching lines @@
 }
 
 void SigninScreenHandler::OnFeedbackFinished() {
   CallJS("login.UnrecoverableCryptohomeErrorScreen.resumeAfterFeedbackUI");
 
   // Recreate user's cryptohome after the feedback is attempted.
   HandleResyncUserData();
 }
 
 }  // namespace chromeos