Move all core files in //components/sessions into core/ subdir

components/sessions/core/session_backend.h

 // Copyright 2011 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_SESSIONS_SESSION_BACKEND_H_
-#define COMPONENTS_SESSIONS_SESSION_BACKEND_H_
+#ifndef COMPONENTS_SESSIONS_CORE_SESSION_BACKEND_H_
+#define COMPONENTS_SESSIONS_CORE_SESSION_BACKEND_H_
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/task/cancelable_task_tracker.h"
-#include "components/sessions/base_session_service.h"
-#include "components/sessions/session_command.h"
-#include "components/sessions/sessions_export.h"
+#include "components/sessions/core/base_session_service.h"
+#include "components/sessions/core/session_command.h"
+#include "components/sessions/core/sessions_export.h"
 
 namespace base {
 class File;
 }
 
 namespace sessions {
 // SessionBackend -------------------------------------------------------------
 
 // SessionBackend is the backend used by BaseSessionService. It is responsible
 // for maintaining two files:
@@ skipping 109 matching lines @@
   bool inited_;
 
   // If true, the file is empty (no commands have been added to it).
   bool empty_file_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionBackend);
 };
 
 }  // namespace sessions
 
-#endif  // COMPONENTS_SESSIONS_SESSION_BACKEND_H_
+#endif  // COMPONENTS_SESSIONS_CORE_SESSION_BACKEND_H_