Move BookmarkExpandedStateTracker into bookmarks namespace.

components/bookmarks/browser/bookmark_expanded_state_tracker.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_BOOKMARKS_BROWSER_BOOKMARK_EXPANDED_STATE_TRACKER_H_
 #define COMPONENTS_BOOKMARKS_BROWSER_BOOKMARK_EXPANDED_STATE_TRACKER_H_
 
 #include <set>
 
 #include "components/bookmarks/browser/base_bookmark_model_observer.h"
 
 class BookmarkModel;
 class BookmarkNode;
 class PrefService;
 
+namespace bookmarks {
+
 // BookmarkExpandedStateTracker is used to track a set of expanded nodes. The
 // nodes are persisted in preferences. If an expanded node is removed from the
 // model BookmarkExpandedStateTracker removes the node.
 class BookmarkExpandedStateTracker : public BaseBookmarkModelObserver {
  public:
   typedef std::set<const BookmarkNode*> Nodes;
 
   BookmarkExpandedStateTracker(BookmarkModel* bookmark_model,
                                PrefService* pref_service);
   virtual ~BookmarkExpandedStateTracker();
@@ skipping 20 matching lines @@
   // Updates the value for |prefs::kBookmarkEditorExpandedNodes| from
   // GetExpandedNodes().
   void UpdatePrefs(const Nodes& nodes);
 
   BookmarkModel* bookmark_model_;
   PrefService* pref_service_;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkExpandedStateTracker);
 };
 
+}  // namespace bookmarks
+
 #endif  // COMPONENTS_BOOKMARKS_BROWSER_BOOKMARK_EXPANDED_STATE_TRACKER_H_