Add the "virtual" keyword on method overrides that are missing it.

chrome/browser/bookmarks/bookmark_storage.h

 // Copyright (c) 2010 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_STORAGE_H_
 #define CHROME_BROWSER_BOOKMARKS_BOOKMARK_STORAGE_H_
 #pragma once
 
 #include "base/file_path.h"
 #include "base/ref_counted.h"
@@ skipping 111 matching lines @@
 
   // Called when history has written the file with bookmarks data. Loads data
   // from that file.
   void OnHistoryFinishedWriting();
 
   // Called after we loaded file generated by history. Saves the data, deletes
   // the temporary file, and notifies the model.
   void FinishHistoryMigration();
 
   // NotificationObserver
-  void Observe(NotificationType type, const NotificationSource& source,
-               const NotificationDetails& details);
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
 
   // Serializes the data and schedules save using ImportantFileWriter.
   // Returns true on successful serialization.
   bool SaveNow();
 
   // Keep the pointer to profile, we may need it for migration from history.
   Profile* profile_;
 
   // The model. The model is NULL once BookmarkModelDeleted has been invoked.
   BookmarkModel* model_;
 
   // Helper to write bookmark data safely.
   ImportantFileWriter writer_;
 
   // Helper to ensure that we unregister from notifications on destruction.
   NotificationRegistrar notification_registrar_;
 
   // Path to temporary file created during migrating bookmarks from history.
   const FilePath tmp_history_path_;
 
   // See class description of BookmarkLoadDetails for details on this.
   scoped_ptr<BookmarkLoadDetails> details_;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkStorage);
 };
 
 #endif  // CHROME_BROWSER_BOOKMARKS_BOOKMARK_STORAGE_H_