Delete dead signin code (SigninGlobalError)

chrome/browser/signin/signin_global_error_factory.h

-// Copyright 2014 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.
-
-#ifndef CHROME_BROWSER_SIGNIN_SIGNIN_GLOBAL_ERROR_FACTORY_H_
-#define CHROME_BROWSER_SIGNIN_SIGNIN_GLOBAL_ERROR_FACTORY_H_
-
-#include "base/memory/singleton.h"
-#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
-
-class SigninGlobalError;
-class Profile;
-
-// Singleton that owns all SigninGlobalErrors and associates them with
-// Profiles. Listens for the Profile's destruction notification and cleans up
-// the associated SigninGlobalError.
-class SigninGlobalErrorFactory : public BrowserContextKeyedServiceFactory {
- public:
-  // Returns the instance of SigninGlobalError associated with this
-  // profile, creating one if none exists. In Ash, this will return NULL.
-  static SigninGlobalError* GetForProfile(Profile* profile);
-
-  // Returns an instance of the SigninGlobalErrorFactory singleton.
-  static SigninGlobalErrorFactory* GetInstance();
-
- private:
-  friend struct DefaultSingletonTraits<SigninGlobalErrorFactory>;
-
-  SigninGlobalErrorFactory();
-  ~SigninGlobalErrorFactory() override;
-
-  // BrowserContextKeyedServiceFactory:
-  KeyedService* BuildServiceInstanceFor(
-      content::BrowserContext* profile) const override;
-
-  DISALLOW_COPY_AND_ASSIGN(SigninGlobalErrorFactory);
-};
-
-#endif  // CHROME_BROWSER_SIGNIN_SIGNIN_GLOBAL_ERROR_FACTORY_H_