Implement an observer interface for the site engagement service.

chrome/browser/engagement/site_engagement_score.h

 // Copyright 2016 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_SCORE_H_
 #define CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SCORE_H_
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/time/time.h"
@@ skipping 12 matching lines @@
     MAX_POINTS_PER_DAY = 0,
 
     // The period over which site engagement decays.
     DECAY_PERIOD_IN_DAYS,
 
     // The number of points to decay per period.
     DECAY_POINTS,
 
     // The number of points given for navigations.
     NAVIGATION_POINTS,
+    POINTS_INCREMENT_FIRST = NAVIGATION_POINTS,
 
     // The number of points given for user input.
     USER_INPUT_POINTS,
 
     // The number of points given for media playing. Initially calibrated such
     // that at least 30 minutes of foreground media would be required to allow a
     // site to reach the daily engagement maximum.
     VISIBLE_MEDIA_POINTS,
     HIDDEN_MEDIA_POINTS,
+    POINTS_INCREMENT_LAST = HIDDEN_MEDIA_POINTS,

[calamity, 2016/05/24 08:09:32]

This won't work if we add a new increment type to the bottom of this enum. We
need either a function or a new enum that tells us exactly what the increment
types are.

[dominickn, 2016/05/25 07:21:32]

Is there any reason to keep this enum append only? Even if we change Finch
configs, there is a mechanism to target experiments to certain versions so that
shouldn't be an issue. I've added a comment to make this more explicit.
Otherwise, the increment stuff isn't really necessary in this CL - I kept it
because it seems like we were missing the complement function for
GetEngagementLevel.

[calamity, 2016/05/31 05:56:35]

Guess not. This whole 3-way mapping is getting a bit messy though =S

 
     // 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,
 
@@ skipping 17 matching lines @@
   static double GetDecayPoints();
   static double GetNavigationPoints();
   static double GetUserInputPoints();
   static double GetVisibleMediaPoints();
   static double GetHiddenMediaPoints();
   static double GetWebAppInstalledPoints();
   static double GetFirstDailyEngagementPoints();
   static double GetBootstrapPoints();
   static double GetMediumEngagementBoundary();
   static double GetHighEngagementBoundary();
+  static double GetMinimumEngagementIncrement();
 
   // Update the default engagement settings via variations.
   static void UpdateFromVariations(const char* param_name);
 
   // The SiteEngagementScore 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 79 matching lines @@
   base::Time last_engagement_time_;
 
   // The last time the site with this score was launched from an installed
   // shortcut.
   base::Time last_shortcut_launch_time_;
 
   DISALLOW_COPY_AND_ASSIGN(SiteEngagementScore);
 };
 
 #endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SCORE_H_