[Android] Persist ordering of NTP suggestions.

chrome/browser/android/most_visited_sites.h

Index: chrome/browser/android/most_visited_sites.h
diff --git a/chrome/browser/android/most_visited_sites.h b/chrome/browser/android/most_visited_sites.h
index 4ecc9676c53e187daa9a3a4bdd2d9d32013f13d7..b2bb66288456b89a8dcc0223b03e9546a440459f 100644
--- a/chrome/browser/android/most_visited_sites.h
+++ b/chrome/browser/android/most_visited_sites.h
@@ -15,7 +15,6 @@
 #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"
@@ -25,8 +24,13 @@ 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,
@@ -53,15 +57,36 @@ class MostVisitedSites : public sync_driver::SyncServiceObserver,
   // Registers JNI methods.
   static bool Register(JNIEnv* env);
 
- private:
-  friend class MostVisitedSitesTest;
+  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // The source of the Most Visited sites.
-  enum MostVisitedSource {
-    TOP_SITES,
-    SUGGESTIONS_SERVICE
+  enum MostVisitedSource { TOP_SITES, SUGGESTIONS_SERVICE, POPULAR };
+
+  struct Suggestion {

[Bernhard Bauer, 2015/09/08 15:44:25]

Can you make this private and only forward-declare in here in the header?

[knn, 2015/09/09 09:35:38]

Made private but can't forward declare as it is used in tests.

+    base::string16 title;
+    std::string url;
+    std::string host;
+    MostVisitedSource source;
+    // Only for source == SUGGESTIONS_SERVICE

[Bernhard Bauer, 2015/09/08 15:44:25]

Document that it's -1 otherwise? (Or at least that it's only guaranteed to be a
valid index if source == SUGGESTIONS_SERVICE)

[knn, 2015/09/09 09:35:38]

Done.

+    int provider_index;
+
+    Suggestion(const base::string16& title,
+               const std::string& url,
+               MostVisitedSource source);
+    Suggestion(const base::string16& title,
+               const std::string& url,
+               const std::string& host,
+               MostVisitedSource source);
+    Suggestion(const base::string16& title,
+               const std::string& url,
+               MostVisitedSource source,
+               int provider_index);

[Bernhard Bauer, 2015/09/08 15:44:25]

Add a destructor?

[knn, 2015/09/09 09:35:38]

Done. Just curious, whether this serves any purpose other than document that I
haven't forgotten?

[Marc Treib, 2015/09/09 09:58:42]

Some trybots check that "non-trivial" structs have a destructor. I ran into that
recently, see https://codereview.chromium.org/1314493013/#ps120001

+    std::string GetSourceHistogramName() const;

[Bernhard Bauer, 2015/09/08 15:44:25]

Add DISALLOW_COPY_AND_ASSIGN if you are not using those methods. If you are, add
a comment that copying and assignment are allowed.

[knn, 2015/09/09 09:35:38]

Done.

   };
 
+ private:
+  friend class MostVisitedSitesTest;
+
   ~MostVisitedSites() override;
   void QueryMostVisitedURLs();
 
@@ -77,25 +102,20 @@ class MostVisitedSites : public sync_driver::SyncServiceObserver,
   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);
+  // Takes the personal suggestions and adds popular suggestions if necessary
+  // and reorders the suggestions based on the previously displayed order.
+  void AddPopularSites(ScopedVector<Suggestion>* suggestions);
 
   // 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 ScopedVector<Suggestion> MergeSuggestions(
+      ScopedVector<Suggestion>* personal_suggestions,
+      ScopedVector<Suggestion>* popular_suggestions,
+      const std::vector<std::string>& old_sites_url,
+      const std::vector<bool>& old_sites_is_personal);
 
   // 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 NotifyMostVisitedURLsObserver();
 
   void OnPopularSitesAvailable(bool success);
 
@@ -155,16 +175,14 @@ class MostVisitedSites : public sync_driver::SyncServiceObserver,
   // In this case a gray tile is used as the main tile.
   int num_empty_thumbs_;
 
-  // Identifier for where each tile came from (client, server, popular). Used
-  // for logging.
-  std::vector<std::string> tile_sources_;
-
   ScopedObserver<history::TopSites, history::TopSitesObserver> scoped_observer_;
 
   MostVisitedSource mv_source_;
 
   scoped_ptr<PopularSites> popular_sites_;
 
+  ScopedVector<Suggestion> current_suggestions_;
+
   // For callbacks may be run after destruction.
   base::WeakPtrFactory<MostVisitedSites> weak_ptr_factory_;