Componentize OriginsSeenService & provide iOS factory.

chrome/browser/tab_contents/origins_seen_service_factory.h

 // Copyright 2016 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_TAB_CONTENTS_ORIGINS_SEEN_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_TAB_CONTENTS_ORIGINS_SEEN_SERVICE_FACTORY_H_
 
 #include "base/memory/singleton.h"
-#include "chrome/browser/tab_contents/origins_seen_service.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
+namespace navigation_metrics {
 class OriginsSeenService;
+}
 
 class OriginsSeenServiceFactory : public BrowserContextKeyedServiceFactory {
  public:
-  static OriginsSeenService* GetForBrowserContext(
+  static navigation_metrics::OriginsSeenService* GetForBrowserContext(
       content::BrowserContext* context);
 
   static OriginsSeenServiceFactory* GetInstance();
 
   // Used to create instances for testing.
   static KeyedService* BuildInstanceFor(content::BrowserContext* context);
 
  private:
   friend struct base::DefaultSingletonTraits<OriginsSeenServiceFactory>;
 
   OriginsSeenServiceFactory();
   ~OriginsSeenServiceFactory() override;
 
   // BrowserContextKeyedServiceFactory:
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_ORIGINS_SEEN_SERVICE_FACTORY_H_