[Android] Persist ordering of NTP suggestions.

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 <string>
 #include <vector>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
-#include "chrome/browser/profiles/profile.h"
 #include "components/history/core/browser/history_types.h"
 #include "components/history/core/browser/top_sites_observer.h"
 #include "components/suggestions/proto/suggestions.pb.h"
 #include "components/sync_driver/sync_service_observer.h"
 
 namespace suggestions {
 class SuggestionsService;
 }
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
 class GURL;
 class PopularSites;
+class Profile;
 
 // Provides the list of most visited sites and their thumbnails to Java.
 class MostVisitedSites : public sync_driver::SyncServiceObserver,
                          public history::TopSitesObserver {
  public:
   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);
 
   // sync_driver::SyncServiceObserver implementation.
   void OnStateChanged() override;
 
   // Registers JNI methods.
   static bool Register(JNIEnv* env);
 
+  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
+
  private:
   friend class MostVisitedSitesTest;
 
   // The source of the Most Visited sites.
   enum MostVisitedSource {
     TOP_SITES,
     SUGGESTIONS_SERVICE
   };
 
   ~MostVisitedSites() override;
   void QueryMostVisitedURLs();
 
   // Initialize the query to Top Sites. Called if the SuggestionsService is not
   // enabled, or if it returns no data.
   void InitiateTopSitesQuery();
 
   // Callback for when data is available from TopSites.
   void OnMostVisitedURLsAvailable(
       const history::MostVisitedURLList& visited_list);
 
   // Callback for when data is available from the SuggestionsService.
   void OnSuggestionsProfileAvailable(
       const suggestions::SuggestionsProfile& suggestions_profile);
 
   // Adds the suggestions from |popular_sites_| into |titles| and |urls|. This
   // might reorder |titles| and |urls| to retain the absolute positions of the
   // popular suggestions. Also updates |tile_sources_| accordingly.
-  void AddPopularSites(std::vector<base::string16>* titles,
-                       std::vector<std::string>* urls);
+  void AddPopularSites(std::vector<base::string16>* result_titles,
+                       std::vector<std::string>* result_urls,
+                       std::vector<base::string16>* personal_titles,
+                       std::vector<std::string>* personal_urls);
 
   // Workhorse for AddPopularSites above. Implemented as a separate static
   // method for ease of testing.
-  static void AddPopularSitesImpl(
-      int num_sites,
-      const std::vector<base::string16>& popular_titles,
-      const std::vector<std::string>& popular_urls,
-      std::vector<base::string16>* titles,
-      std::vector<std::string>* urls,
-      std::vector<std::string>* tile_sources);
+  static void MergeSuggestions(
+      // Return values.
+      std::vector<bool>* result_is_personal,
+      std::vector<std::string>* result_urls,
+      std::vector<base::string16>* result_titles,
+      // Arguments.
+      size_t num_tiles,
+      size_t num_personal_suggestions,

[Bernhard Bauer, 2015/09/07 11:22:58]

This is the number of elements in |personal_*| below, right? Why do we need to
pass it in again?

[knn, 2015/09/08 10:48:56]

Yes not required.

+      size_t num_popular_suggestions,
+      // Passed as ptr for move semantics only.

[Bernhard Bauer, 2015/09/07 11:22:58]

I don't quite understand what you mean by move semantics here. To allow
modification (which would include moving elements out of the container)?

[knn, 2015/09/08 10:48:56]

Yes.

+      std::vector<std::string>* personal_urls,

[Bernhard Bauer, 2015/09/07 11:22:58]

Could we put all of these into a ScopedVector of some struct? Something like:

  struct Suggestion {
    base::string16 title;
    string url;
  };

And then extend as necessary and pass a ScopedVector for each of personal
suggestions, popular suggestions, and output... or something.

[Marc Treib, 2015/09/07 11:32:07]

+1 for the struct, but why ScopedVector? A regular vector should do just fine?!

[knn, 2015/09/08 10:48:56]

Done.

+      std::vector<base::string16>* personal_titles,
+      std::vector<std::string>* popular_urls,
+      std::vector<base::string16>* popular_titles,
+      const std::vector<std::string>& personal_hosts,
+      const std::vector<std::string>& popular_hosts,
+      const std::vector<std::string>& old_sites_url,
+      // Whether the site is a personal suggestion.
+      const std::vector<bool>& old_sites_source);
 
   // Notify the Java side observer about the availability of Most Visited Urls.
   void NotifyMostVisitedURLsObserver(const std::vector<base::string16>& titles,
                                      const std::vector<std::string>& urls);
 
   void OnPopularSitesAvailable(bool success);
 
   // Runs on the UI Thread.
   void OnLocalThumbnailFetched(
       const GURL& url,
@@ skipping 60 matching lines @@
 
   scoped_ptr<PopularSites> popular_sites_;
 
   // For callbacks may be run after destruction.
   base::WeakPtrFactory<MostVisitedSites> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MostVisitedSites);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_MOST_VISITED_SITES_H_