[sessions] Properly namespace recently-componentized TabRestore code

components/sessions/core/serialized_navigation_driver.h

 // Copyright 2014 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_CORE_SERIALIZED_NAVIGATION_DRIVER_H_
 #define COMPONENTS_SESSIONS_CORE_SERIALIZED_NAVIGATION_DRIVER_H_
 
 #include <string>
 
 #include "components/sessions/sessions_export.h"
 
 namespace sessions {
+
 class SerializedNavigationEntry;
 
 // The SerializedNavigationDriver interface allows SerializedNavigationEntry to
 // obtain information from a singleton driver object. A concrete implementation
 // must be provided by the driver on each platform.
 class SESSIONS_EXPORT_PRIVATE SerializedNavigationDriver {
  public:
   virtual ~SerializedNavigationDriver() {}
 
   // Returns the singleton SerializedNavigationDriver.
@@ skipping 24 matching lines @@
   virtual void Sanitize(SerializedNavigationEntry* navigation) const = 0;
 
   // Removes the referrer from the encoded page state.
   virtual std::string StripReferrerFromPageState(
       const std::string& page_state) const = 0;
 };
 
 }  // namespace sessions
 
 #endif  // COMPONENTS_SESSIONS_CORE_SERIALIZED_NAVIGATION_DRIVER_H_