More consistency in m_v_s_bridge.cc.

chrome/browser/android/ntp/most_visited_sites.h

Index: chrome/browser/android/ntp/most_visited_sites.h
diff --git a/chrome/browser/android/ntp/most_visited_sites.h b/chrome/browser/android/ntp/most_visited_sites.h
index bbbd5d217d75f4f15d77fb828cb7eec14ce9274f..3939ee745c578d594d8cd2a7958082e0177b319d 100644
--- a/chrome/browser/android/ntp/most_visited_sites.h
+++ b/chrome/browser/android/ntp/most_visited_sites.h
@@ -56,11 +56,12 @@ class MostVisitedSites : public history::TopSitesObserver,
   // 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 {