[Most Visited] Check for Sync state when using SuggestionsService.

chrome/browser/android/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_MOST_VISITED_SITES_H_
 #define CHROME_BROWSER_ANDROID_MOST_VISITED_SITES_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/sync/profile_sync_service_observer.h"
 #include "components/suggestions/proto/suggestions.pb.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 namespace suggestions {
 class SuggestionsService;
 }
 
 // Provides the list of most visited sites and their thumbnails to Java.
-class MostVisitedSites : public content::NotificationObserver {
+class MostVisitedSites : public ProfileSyncServiceObserver,
+                         public content::NotificationObserver {
  public:
   typedef base::Callback<
       void(base::android::ScopedJavaGlobalRef<jobject>* bitmap,
            base::android::ScopedJavaGlobalRef<jobject>* j_callback)>
       LookupSuccessCallback;
 
   explicit MostVisitedSites(Profile* profile);
   void Destroy(JNIEnv* env, jobject obj);
   void OnLoadingComplete(JNIEnv* env, jobject obj);
   void SetMostVisitedURLsObserver(JNIEnv* env,
                                   jobject obj,
                                   jobject j_observer,
                                   jint num_sites);
   void GetURLThumbnail(JNIEnv* env,
                        jobject obj,
                        jstring url,
                        jobject j_callback);
   void BlacklistUrl(JNIEnv* env, jobject obj, jstring j_url);
   void RecordOpenedMostVisitedItem(JNIEnv* env, jobject obj, jint index);
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // ProfileSyncServiceObserver implementation.
+  virtual void OnStateChanged() OVERRIDE;
+
   // Registers JNI methods.
   static bool Register(JNIEnv* env);
 
  private:
   virtual ~MostVisitedSites();
   void QueryMostVisitedURLs();
 
   // Initialize the query to Top Sites. Called if the SuggestionsService is not
   // enabled, or if it returns no data.
   void InitiateTopSitesQuery();
@@ skipping 63 matching lines @@
   enum MostVisitedSource {
     TOP_SITES,
     SUGGESTIONS_SERVICE
   };
   MostVisitedSource mv_source_;
 
   DISALLOW_COPY_AND_ASSIGN(MostVisitedSites);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_MOST_VISITED_SITES_H_