Add an IsBootstrapped method to the SiteEngagementService.

chrome/browser/engagement/site_engagement_service.h

 // Copyright 2015 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_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_
 #define CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_
 
 #include <map>
 #include <set>
 
@@ skipping 42 matching lines @@
 
     // The number of points added to engagement when a site is launched from
     // homescreen or added as a bookmark app. This bonus will apply for ten days
     // following a launch; each new launch resets the ten days.
     WEB_APP_INSTALLED_POINTS,
 
     // The number of points given for the first engagement event of the day for
     // each site.
     FIRST_DAILY_ENGAGEMENT,
 
+    // The number of points that the engagement service must accumulate to be
+    // considered 'useful'.
+    BOOTSTRAP_POINTS,
+
     MAX_VARIATION
   };
 
   // The maximum number of points that are allowed.
   static const double kMaxPoints;
 
   static double GetMaxPointsPerDay();
   static double GetDecayPeriodInDays();
   static double GetDecayPoints();
   static double GetNavigationPoints();
   static double GetUserInputPoints();
   static double GetVisibleMediaPoints();
   static double GetHiddenMediaPoints();
   static double GetWebAppInstalledPoints();
   static double GetFirstDailyEngagementPoints();
+  static double GetBootstrapPoints();
 
   // Update the default engagement settings via variations.
   static void UpdateFromVariations();
 
   // The SiteEngagementService does not take ownership of |clock|. It is the
   // responsibility of the caller to make sure |clock| outlives this
   // SiteEngagementScore.
   SiteEngagementScore(base::Clock* clock,
                       const base::DictionaryValue& score_dict);
   ~SiteEngagementScore();
@@ skipping 102 matching lines @@
 
   // Returns whether or not the SiteEngagementService is enabled.
   static bool IsEnabled();
 
   explicit SiteEngagementService(Profile* profile);
   ~SiteEngagementService() override;
 
   // Returns a map of all stored origins and their engagement scores.
   std::map<GURL, double> GetScoreMap();
 
+  // Returns whether the engagement service has enough data to make meaningful
+  // decisions. Clients should avoid using engagement in their heuristic until
+  // this is true.
+  bool IsBootstrapped();
+
   // Update the engagement score of the origin matching |url| for navigation.
   void HandleNavigation(const GURL& url, ui::PageTransition transition);
 
   // Update the engagement score of the origin matching |url| for time-on-site,
   // based on user input.
   void HandleUserInput(const GURL& url,
                        SiteEngagementMetrics::EngagementType type);
 
   // Update the engagement score of the origin matching |url| for media playing.
   // The points awarded are discounted if the media is being played in a non-
@@ skipping 21 matching lines @@
  private:
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, CheckHistograms);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, CleanupEngagementScores);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, ClearHistoryForURLs);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, GetMedianEngagement);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, GetTotalNavigationPoints);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, GetTotalUserInputPoints);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, LastShortcutLaunch);
   FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest,
                            CleanupOriginsOnHistoryDeletion);
+  FRIEND_TEST_ALL_PREFIXES(SiteEngagementServiceTest, IsBootstrapped);
   FRIEND_TEST_ALL_PREFIXES(AppBannerSettingsHelperTest, SiteEngagementTrigger);
 
   // Only used in tests.
   SiteEngagementService(Profile* profile, scoped_ptr<base::Clock> clock);
 
   // Adds the specified number of points to the given origin, respecting the
   // maximum limits for the day and overall.
   void AddPoints(const GURL& url, double points);
 
   // Post startup tasks: cleaning up origins which have decayed to 0, and
@@ skipping 24 matching lines @@
   // origin's engagement score after an hour has elapsed triggers the next
   // upload.
   base::Time last_metrics_time_;
 
   base::WeakPtrFactory<SiteEngagementService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SiteEngagementService);
 };
 
 #endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_