Popular sites on the NTP: re-download popular suggestions once per Chrome run

chrome/browser/android/most_visited_sites.cc

 // 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.
 
 #include "chrome/browser/android/most_visited_sites.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 116 matching lines @@
     return true;
   return base::StartsWith(group_name, "Enabled",
                           base::CompareCase::INSENSITIVE_ASCII);
 }
 
 std::string GetPopularSitesFilename() {
   return variations::GetVariationParamValue(kPopularSitesFieldTrialName,
                                             "filename");
 }
 
+// Determine whether we need any popular suggestions to fill up a grid of
+// |num_tiles| tiles.
+bool NeedPopularSites(const PrefService* prefs, size_t num_tiles) {
+  const base::ListValue* source_list =
+      prefs->GetList(prefs::kNTPSuggestionsIsPersonal);
+  // If there aren't enough previous suggestions to fill the grid, we need
+  // popular suggestions.
+  if (source_list->GetSize() < num_tiles)
+    return true;
+  // Otherwise, if any of the previous suggestions is not personal, then also
+  // get popular suggestions.
+  for (size_t i = 0; i < num_tiles; ++i) {
+    bool is_personal = false;
+    if (source_list->GetBoolean(i, &is_personal) && !is_personal)
+      return true;
+  }
+  // The whole grid is already filled with personal suggestions, no point in
+  // bothering with popular ones.
+  return false;
+}
+
 }  // namespace
 
 MostVisitedSites::Suggestion::Suggestion(const base::string16& title,
                                          const std::string& url,
                                          MostVisitedSource source)
     : title(title), url(url), source(source), provider_index(-1) {}
 
 MostVisitedSites::Suggestion::Suggestion(const base::string16& title,
                                          const GURL& url,
                                          MostVisitedSource source)
@@ skipping 35 matching lines @@
                               new suggestions::SuggestionsSource(profile_));
   content::URLDataSource::Add(profile_, new ThumbnailListSource(profile_));
 
   // Register this class as an observer to the sync service. It is important to
   // be notified of changes in the sync state such as initialization, sync
   // being enabled or disabled, etc.
   ProfileSyncService* profile_sync_service =
       ProfileSyncServiceFactory::GetForProfile(profile_);
   if (profile_sync_service)
     profile_sync_service->AddObserver(this);
-
-  if (ShouldShowPopularSites()) {
-    popular_sites_.reset(new PopularSites(
-        profile,
-        GetPopularSitesFilename(),
-        profile_->GetRequestContext(),
-        base::Bind(&MostVisitedSites::OnPopularSitesAvailable,
-                   base::Unretained(this))));
-  } else {
-    received_popular_sites_ = true;
-  }
 }
 
 MostVisitedSites::~MostVisitedSites() {
   ProfileSyncService* profile_sync_service =
       ProfileSyncServiceFactory::GetForProfile(profile_);
   if (profile_sync_service && profile_sync_service->HasObserver(this))
     profile_sync_service->RemoveObserver(this);
 }
 
 void MostVisitedSites::Destroy(JNIEnv* env, jobject obj) {
   delete this;
 }
 
 void MostVisitedSites::OnLoadingComplete(JNIEnv* env, jobject obj) {
   RecordThumbnailUMAMetrics();
 }
 
 void MostVisitedSites::SetMostVisitedURLsObserver(JNIEnv* env,
                                                   jobject obj,
                                                   jobject j_observer,
                                                   jint num_sites) {
   observer_.Reset(env, j_observer);
   num_sites_ = num_sites;
 
+  if (ShouldShowPopularSites() &&
+      NeedPopularSites(profile_->GetPrefs(), num_sites_)) {
+    popular_sites_.reset(new PopularSites(
+        profile_,
+        GetPopularSitesFilename(),
+        profile_->GetRequestContext(),
+        base::Bind(&MostVisitedSites::OnPopularSitesAvailable,
+                   base::Unretained(this))));
+  } else {
+    received_popular_sites_ = true;
+  }
+
   QueryMostVisitedURLs();
 
   scoped_refptr<history::TopSites> top_sites =
       TopSitesFactory::GetForProfile(profile_);
   if (top_sites) {
     // TopSites updates itself after a delay. To ensure up-to-date results,
     // force an update now.
     top_sites->SyncWithHistory();
 
     // Register as TopSitesObserver so that we can update ourselves when the
@@ skipping 468 matching lines @@
   }
 }
 
 static jlong Init(JNIEnv* env,
                   const JavaParamRef<jobject>& obj,
                   const JavaParamRef<jobject>& jprofile) {
   MostVisitedSites* most_visited_sites =
       new MostVisitedSites(ProfileAndroid::FromProfileAndroid(jprofile));
   return reinterpret_cast<intptr_t>(most_visited_sites);
 }