Make the SigninErrorController a PKS.

chrome/browser/signin/signin_error_controller_factory.h

Index: chrome/browser/signin/signin_error_controller_factory.h
diff --git a/chrome/browser/signin/signin_error_controller_factory.h b/chrome/browser/signin/signin_error_controller_factory.h
new file mode 100644
index 0000000000000000000000000000000000000000..990243e639bcc4fa3126b12cdfadf84bd37248ad
--- /dev/null
+++ b/chrome/browser/signin/signin_error_controller_factory.h
@@ -0,0 +1,37 @@
+// Copyright 2015 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_ERROR_CONTROLLER_FACTORY_H_
+#define CHROME_BROWSER_SIGNIN_SIGNIN_ERROR_CONTROLLER_FACTORY_H_
+
+#include "base/memory/singleton.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+#include "components/signin/core/browser/signin_error_controller.h"
+
+class Profile;
+
+// Singleton that owns all SigninErrorControllers and associates them with
+// Profiles.
+class SigninErrorControllerFactory : public BrowserContextKeyedServiceFactory {
+ public:
+  // Returns the instance of SigninErrorController associated with this profile
+  // (creating one if none exists). Returns NULL if this profile cannot have an
+  // SigninClient (for example, if |profile| is incognito).
+  static SigninErrorController* GetForProfile(Profile* profile);
+
+  // Returns an instance of the factory singleton.
+  static SigninErrorControllerFactory* GetInstance();
+
+ private:
+  friend struct DefaultSingletonTraits<SigninErrorControllerFactory>;
+
+  SigninErrorControllerFactory();
+  ~SigninErrorControllerFactory() override;
+
+  // BrowserContextKeyedServiceFactory:
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* profile) const override;
+};
+
+#endif  // CHROME_BROWSER_SIGNIN_SIGNIN_ERROR_CONTROLLER_FACTORY_H_