Set site engagement timestamps to privacy-respectful values when history is cleared.

chrome/browser/engagement/site_engagement_service.h

Index: chrome/browser/engagement/site_engagement_service.h
diff --git a/chrome/browser/engagement/site_engagement_service.h b/chrome/browser/engagement/site_engagement_service.h
index 4cfdc78a6f7d6891be8c25f2a1993f5be06fe73c..6e98186b21f561f644037dbecdbc91f636a8d68b 100644
--- a/chrome/browser/engagement/site_engagement_service.h
+++ b/chrome/browser/engagement/site_engagement_service.h
@@ -22,6 +22,10 @@ class DictionaryValue;
 class Clock;
 }
 
+namespace history {
+class HistoryService;
+}
+
 class GURL;
 class Profile;
 
@@ -101,8 +105,16 @@ class SiteEngagementScore {
   double Score() const;
   void AddPoints(double points);
 
-  // Resets the score to |points| and reset the daily point limit.
-  void Reset(double points);
+  // Resets the score to |points| and resets the daily point limit. If
+  // |updated_time| is non-null, sets the last engagement time and last
+  // shortcut launch time (if it is non-null) to |updated_time|. Othewise, last

[benwells, 2016/04/18 07:01:42]

Typo in Othewise.

[dominickn, 2016/04/18 23:27:52]

Done.

+  // engagement time is set to the current time and last shortcut launch time is
+  // left unchanged.
+  // TODO(calamity): Ideally, all SiteEngagementScore methods should take a

[benwells, 2016/04/18 07:01:42]

Could you file a bug and refer to it here?

[dominickn, 2016/04/18 23:27:52]

Done.

+  // base::Time argument like this one does rather than each Score hold a
+  // pointer to a base::Clock. Then SiteEngagementScore doesn't need to worry
+  // about clock vending - it's always told what time to use.
+  void Reset(double points, const base::Time* updated_time);
 
   // Returns true if the maximum number of points today has been added.
   bool MaxPointsPerDayAdded() const;
@@ -299,10 +311,18 @@ class SiteEngagementService : public KeyedService,
   int OriginsWithMaxEngagement(const std::map<GURL, double>& score_map) const;
 
   void GetCountsForOriginsComplete(
+    history::HistoryService* history_service,
     const std::multiset<GURL>& deleted_url_origins,
     bool expired,
     const history::OriginCountMap& remaining_origin_counts);
 
+  // Resets the engagement score for |url| to |score|, and sets the last
+  // engagement time and last shortcut launch time (if it is non-null) to
+  // |updated_time|. Clears daily limits.
+  void ResetScoreAndAccessTimesForURL(const GURL& url,
+                                      double score,
+                                      const base::Time* updated_time);
+
   Profile* profile_;
 
   // The clock used to vend times.