[sessions] Properly namespace recently-componentized TabRestore code

components/sessions/core/tab_restore_service.cc

 // Copyright (c) 2012 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.
 
 #include "components/sessions/core/tab_restore_service.h"
 
+namespace sessions {
+
 // TimeFactory-----------------------------------------------------------------
 
 TabRestoreService::TimeFactory::~TimeFactory() {}
 
 // Entry ----------------------------------------------------------------------
 
 // ID of the next Entry.
 static SessionID::id_type next_entry_id = 1;
 
 TabRestoreService::Entry::Entry()
@@ skipping 55 matching lines @@
 TabRestoreService::Window::Window() : Entry(WINDOW), selected_tab_index(-1) {
 }
 
 TabRestoreService::Window::~Window() {
 }
 
 // TabRestoreService ----------------------------------------------------------
 
 TabRestoreService::~TabRestoreService() {
 }
+
+}  // namespace sessions