bookmarks: Change BookmarkExpandedStateTracker to take PrefService.

chrome/browser/bookmarks/bookmark_expanded_state_tracker.h

 // 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.
 
 #ifndef CHROME_BROWSER_BOOKMARKS_BOOKMARK_EXPANDED_STATE_TRACKER_H_
 #define CHROME_BROWSER_BOOKMARKS_BOOKMARK_EXPANDED_STATE_TRACKER_H_
 
 #include <set>
 
 #include "chrome/browser/bookmarks/base_bookmark_model_observer.h"
 
+class BookmarkModel;
 class BookmarkNode;
-class BookmarkModel;
-
-namespace content {
-class BrowserContext;
-}
+class PrefService;
 
 // 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(content::BrowserContext* browser_context,
-                               BookmarkModel* bookmark_model);
+  BookmarkExpandedStateTracker(BookmarkModel* bookmark_model,
+                               PrefService* pref_service);
   virtual ~BookmarkExpandedStateTracker();
 
   // The set of expanded nodes.
   void SetExpandedNodes(const Nodes& nodes);
   Nodes GetExpandedNodes();
 
  private:
   // BaseBookmarkModelObserver:
   virtual void Loaded(BookmarkModel* model, bool ids_reassigned) OVERRIDE;
   virtual void BookmarkModelChanged() OVERRIDE;
   virtual void BookmarkModelBeingDeleted(BookmarkModel* model) OVERRIDE;
   virtual void BookmarkNodeRemoved(BookmarkModel* model,
                                    const BookmarkNode* parent,
                                    int old_index,
                                    const BookmarkNode* node) OVERRIDE;
   virtual void BookmarkAllNodesRemoved(BookmarkModel* model) OVERRIDE;
 
-  // Resets the value in preferences from |expanded_nodes_|.
+  // Updates the value for |prefs::kBookmarkEditorExpandedNodes| from
+  // GetExpandedNodes().
   void UpdatePrefs(const Nodes& nodes);
 
-  content::BrowserContext* browser_context_;
-
   BookmarkModel* bookmark_model_;
+  PrefService* pref_service_;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkExpandedStateTracker);
 };
 
 #endif  // CHROME_BROWSER_BOOKMARKS_BOOKMARK_EXPANDED_STATE_TRACKER_H_