Update MostVisitedSites observer interface.

chrome/browser/android/ntp/popular_sites.h

Index: chrome/browser/android/ntp/popular_sites.h
diff --git a/chrome/browser/android/ntp/popular_sites.h b/chrome/browser/android/ntp/popular_sites.h
index 7cc520e93e23d89d4c8660a786c49df1c1a1a676..656b7b3709154b6d043280974a16d04d482871da 100644
--- a/chrome/browser/android/ntp/popular_sites.h
+++ b/chrome/browser/android/ntp/popular_sites.h
@@ -27,27 +27,28 @@ class PrefRegistrySyncable;
 
 class Profile;
 
+struct PopularSites_Site {
+  PopularSites_Site(const base::string16& title,
+                    const GURL& url,
+                    const GURL& favicon_url,
+                    const GURL& large_icon_url,
+                    const GURL& thumbnail_url);
+  PopularSites_Site(const PopularSites_Site& other);
+  ~PopularSites_Site();
+
+  base::string16 title;
+  GURL url;
+  GURL favicon_url;
+  GURL large_icon_url;
+  GURL thumbnail_url;
+};
+
 // Downloads and provides a list of suggested popular sites, for display on
 // the NTP when there are not enough personalized suggestions. Caches the
 // downloaded file on disk to avoid re-downloading on every startup.
 class PopularSites {
  public:
-  struct Site {
-    Site(const base::string16& title,
-         const GURL& url,
-         const GURL& favicon_url,
-         const GURL& large_icon_url,
-         const GURL& thumbnail_url);
-    Site(const Site& other);
-    ~Site();
-
-    base::string16 title;
-    GURL url;
-    GURL favicon_url;
-    GURL large_icon_url;
-    GURL thumbnail_url;
-  };
-
+  using Site = PopularSites_Site;
   using FinishedCallback = base::Callback<void(bool /* success */)>;
 
   // Usually, the name of the file that's downloaded is based on the user's