[Sync] Creating sync_sessions component, moving revisit logic.

components/sync_sessions/revisit/sessions_page_revisit_observer.h

 // 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 COMPONENTS_SYNC_DRIVER_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_
-#define COMPONENTS_SYNC_DRIVER_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_
+#ifndef COMPONENTS_SYNC_SESSIONS_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_
+#define COMPONENTS_SYNC_SESSIONS_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_
 
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "components/sync_driver/revisit/page_visit_observer.h"
+#include "components/sync_sessions/revisit/page_visit_observer.h"
 #include "url/gurl.h"
 
 namespace sessions {
 struct SessionTab;
 }  // namespace sessions
 
 namespace sync_driver {
+struct SyncedSession;
+}  // namespace sync_driver
 
-struct SyncedSession;
+namespace sync_sessions {
 
 class CurrentTabMatcher;
 class OffsetTabMatcher;
 
 // A simple interface to abstract away who is providing sessions.
 class ForeignSessionsProvider {
  public:
   // Fills the already instantiated passed vector with all foreign sessions.
   // Returned boolean representes if there were foreign sessions and the vector
   // should be examimed.
@@ skipping 21 matching lines @@
   // Although the signature is identical to OnPageVisit(...), this method
   // actually does all of the work. The assumption is that this method is the
   // target of a PostTask call coming from OnPageVisit(...).
   void CheckForRevisit(const GURL& url, const TransitionType transition);
 
   scoped_ptr<ForeignSessionsProvider> provider_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionsPageRevisitObserver);
 };
 
-}  // namespace sync_driver
+}  // namespace sync_sessions
 
-#endif  // COMPONENTS_SYNC_DRIVER_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_
+#endif  // COMPONENTS_SYNC_SESSIONS_REVISIT_SESSIONS_PAGE_REVISIT_OBSERVER_H_