More consistency in m_v_s_bridge.cc.

chrome/browser/android/ntp/most_visited_sites.h

 // Copyright 2013 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_ANDROID_NTP_MOST_VISITED_SITES_H_
 #define CHROME_BROWSER_ANDROID_NTP_MOST_VISITED_SITES_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 38 matching lines @@
   struct Suggestion;
   using SuggestionsVector = std::vector<Suggestion>;
   using PopularSitesVector = std::vector<PopularSites::Site>;
 
   // The source of the Most Visited sites.
   enum MostVisitedSource { TOP_SITES, SUGGESTIONS_SERVICE, POPULAR, WHITELIST };
 
   // The observer to be notified when the list of most visited sites changes.
   class Observer {
    public:
-    virtual ~Observer() {}
-
     virtual void OnMostVisitedURLsAvailable(
         const SuggestionsVector& suggestions) = 0;
     virtual void OnPopularURLsAvailable(const PopularSitesVector& sites) = 0;
+
+   protected:
+    virtual ~Observer() {}
   };
 
   struct Suggestion {
     base::string16 title;
     GURL url;
     MostVisitedSource source;
 
     // Only valid for source == WHITELIST (empty otherwise).
     base::FilePath whitelist_icon_path;
 
@@ skipping 166 matching lines @@
 
   SuggestionsVector current_suggestions_;
 
   // For callbacks may be run after destruction.
   base::WeakPtrFactory<MostVisitedSites> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MostVisitedSites);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_NTP_MOST_VISITED_SITES_H_