Componentize OriginsSeenService & provide iOS factory.

components/navigation_metrics/origins_seen_service.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_H_
-#define CHROME_BROWSER_TAB_CONTENTS_ORIGINS_SEEN_SERVICE_H_
+#ifndef COMPONENTS_NAVIGATION_METRICS_ORIGINS_SEEN_SERVICE_H_
+#define COMPONENTS_NAVIGATION_METRICS_ORIGINS_SEEN_SERVICE_H_
 
 #include "base/containers/mru_cache.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "url/origin.h"
 
+namespace navigation_metrics {
+
 class OriginsSeenService : public KeyedService {
  public:
   OriginsSeenService();
   ~OriginsSeenService() override;
 
   // Used when deciding whether or not to record
   // Navigation.SchemePerUniqueOrigin[OTR]. Inserts a copy of |origin| into the
   // set |origins_seen_|, and returns whether or not |origin| was already in the
   // set.
   bool Insert(const url::Origin& origin);
 
  private:
   // Used by |HaveAlreadySeenOrigin|. This cache is in volatile storage because
   // Off The Record Profiles also use this Service.
   base::MRUCache<url::Origin, bool> origins_seen_;
 };
 
-#endif  // CHROME_BROWSER_TAB_CONTENTS_ORIGINS_SEEN_SERVICE_H_
+}  // namespace navigation_metrics
+
+#endif  // COMPONENTS_NAVIGATION_METRICS_ORIGINS_SEEN_SERVICE_H_