Implement an observer interface for the site engagement service.

chrome/browser/engagement/site_engagement_service.cc

 // 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.
 
 #include "chrome/browser/engagement/site_engagement_service.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <utility>
@@ skipping 149 matching lines @@
   }
 
   return score_map;
 }
 
 bool SiteEngagementService::IsBootstrapped() const {
   return GetTotalEngagementPoints() >=
          SiteEngagementScore::GetBootstrapPoints();
 }
 
-bool SiteEngagementService::IsEngagementAtLeast(
-    const GURL& url,
-    EngagementLevel level) const {
+bool SiteEngagementService::IsEngagementAtLeast(const GURL& url,
+                                                EngagementLevel level) const {
   DCHECK_LT(SiteEngagementScore::GetMediumEngagementBoundary(),
             SiteEngagementScore::GetHighEngagementBoundary());
   double score = GetScore(url);
   switch (level) {
     case ENGAGEMENT_LEVEL_NONE:
       return true;
     case ENGAGEMENT_LEVEL_LOW:
       return score > 0;
     case ENGAGEMENT_LEVEL_MEDIUM:
       return score >= SiteEngagementScore::GetMediumEngagementBoundary();
     case ENGAGEMENT_LEVEL_HIGH:
       return score >= SiteEngagementScore::GetHighEngagementBoundary();
     case ENGAGEMENT_LEVEL_MAX:
       return score == SiteEngagementScore::kMaxPoints;
   }
   NOTREACHED();
   return false;
 }
 
+void SiteEngagementService::AddObserver(SiteEngagementObserver* observer) {
+  observer_list_.AddObserver(observer);
+}
+
+void SiteEngagementService::RemoveObserver(SiteEngagementObserver* observer) {
+  observer_list_.RemoveObserver(observer);
+}
+
 void SiteEngagementService::ResetScoreForURL(const GURL& url, double score) {
   SiteEngagementScore engagement_score = CreateEngagementScore(url);
   engagement_score.Reset(score, clock_->Now());
   engagement_score.Commit();
 }
 
 void SiteEngagementService::SetLastShortcutLaunchTime(const GURL& url) {
   SiteEngagementScore score = CreateEngagementScore(url);
 
   // Record the number of days since the last launch in UMA. If the user's clock
@@ skipping 42 matching lines @@
   score.Commit();
 }
 
 void SiteEngagementService::AfterStartupTask() {
   CleanupEngagementScores();
   RecordMetrics();
 }
 
 void SiteEngagementService::CleanupEngagementScores() {
   HostContentSettingsMap* settings_map =
-    HostContentSettingsMapFactory::GetForProfile(profile_);
+      HostContentSettingsMapFactory::GetForProfile(profile_);
   std::unique_ptr<ContentSettingsForOneType> engagement_settings =
       GetEngagementContentSettings(settings_map);
 
   for (const auto& site : *engagement_settings) {
     GURL origin(site.primary_pattern.ToString());
     if (origin.is_valid() && GetScore(origin) != 0)
-        continue;
+      continue;
 
     settings_map->SetWebsiteSettingDefaultScope(
         origin, GURL(), CONTENT_SETTINGS_TYPE_SITE_ENGAGEMENT, std::string(),
         nullptr);
   }
 }
 
 void SiteEngagementService::RecordMetrics() {
   base::Time now = clock_->Now();
   if (last_metrics_time_.is_null() ||
       (now - last_metrics_time_).InMinutes() >= kMetricsIntervalInMinutes) {
     last_metrics_time_ = now;
     std::map<GURL, double> score_map = GetScoreMap();
 
     int origins_with_max_engagement = OriginsWithMaxEngagement(score_map);
     int total_origins = score_map.size();
     int percent_origins_with_max_engagement =
-        (total_origins == 0 ? 0 : (origins_with_max_engagement * 100) /
-                                      total_origins);
+        (total_origins == 0
+             ? 0
+             : (origins_with_max_engagement * 100) / total_origins);
 
     double total_engagement = GetTotalEngagementPoints();
     double mean_engagement =
         (total_origins == 0 ? 0 : total_engagement / total_origins);
 
     SiteEngagementMetrics::RecordTotalOriginsEngaged(total_origins);
     SiteEngagementMetrics::RecordTotalSiteEngagement(total_engagement);
     SiteEngagementMetrics::RecordMeanEngagement(mean_engagement);
     SiteEngagementMetrics::RecordMedianEngagement(
         GetMedianEngagement(score_map));
@@ skipping 23 matching lines @@
   // scores otherwise.
   std::sort(scores.begin(), scores.end());
   size_t mid = scores.size() / 2;
   if (scores.size() % 2 == 1)
     return scores[mid];
   else
     return (scores[mid - 1] + scores[mid]) / 2;
 }
 
 void SiteEngagementService::HandleMediaPlaying(
-    content::WebContents* web_contents, bool is_hidden) {
+    content::WebContents* web_contents,
+    bool is_hidden) {
+  const GURL& url = web_contents->GetVisibleURL();
   SiteEngagementMetrics::RecordEngagement(
       is_hidden ? SiteEngagementMetrics::ENGAGEMENT_MEDIA_HIDDEN
                 : SiteEngagementMetrics::ENGAGEMENT_MEDIA_VISIBLE);
-  AddPoints(web_contents->GetVisibleURL(),
-            is_hidden ? SiteEngagementScore::GetHiddenMediaPoints()
-                      : SiteEngagementScore::GetVisibleMediaPoints());
+  AddPoints(url, is_hidden ? SiteEngagementScore::GetHiddenMediaPoints()
+                           : SiteEngagementScore::GetVisibleMediaPoints());
+
   RecordMetrics();
+  FOR_EACH_OBSERVER(
+      SiteEngagementObserver, observer_list_,
+      OnEngagementIncreased(web_contents, url, GetScore(url)));
 }
 
 void SiteEngagementService::HandleNavigation(content::WebContents* web_contents,
                                              ui::PageTransition transition) {
   if (IsEngagementNavigation(transition)) {
+    const GURL& url = web_contents->GetLastCommittedURL();
     SiteEngagementMetrics::RecordEngagement(
         SiteEngagementMetrics::ENGAGEMENT_NAVIGATION);
-    AddPoints(web_contents->GetLastCommittedURL(),
-              SiteEngagementScore::GetNavigationPoints());
+    AddPoints(url, SiteEngagementScore::GetNavigationPoints());
+
     RecordMetrics();
+    FOR_EACH_OBSERVER(
+        SiteEngagementObserver, observer_list_,
+        OnEngagementIncreased(web_contents, url, GetScore(url)));
   }
 }
 
 void SiteEngagementService::HandleUserInput(
     content::WebContents* web_contents,
     SiteEngagementMetrics::EngagementType type) {
+  const GURL& url = web_contents->GetVisibleURL();
   SiteEngagementMetrics::RecordEngagement(type);
-  AddPoints(web_contents->GetVisibleURL(),
-            SiteEngagementScore::GetUserInputPoints());
+  AddPoints(url, SiteEngagementScore::GetUserInputPoints());
+
   RecordMetrics();
+  FOR_EACH_OBSERVER(
+      SiteEngagementObserver, observer_list_,
+      OnEngagementIncreased(web_contents, url, GetScore(url)));
 }
 
 void SiteEngagementService::OnURLsDeleted(
     history::HistoryService* history_service,
     bool all_history,
     bool expired,
     const history::URLRows& deleted_rows,
     const std::set<GURL>& favicon_urls) {
   std::multiset<GURL> origins;
   for (const history::URLRow& row : deleted_rows)
@@ skipping 52 matching lines @@
       ++total_origins;
 
   return total_origins;
 }
 
 void SiteEngagementService::GetCountsAndLastVisitForOriginsComplete(
     history::HistoryService* history_service,
     const std::multiset<GURL>& deleted_origins,
     bool expired,
     const history::OriginCountAndLastVisitMap& remaining_origins) {
-
   // The most in-the-past option in the Clear Browsing Dialog aside from "all
   // time" is 4 weeks ago. Set the last updated date to 4 weeks ago for origins
   // where we can't find a valid last visit date.
   base::Time now = clock_->Now();
   base::Time four_weeks_ago =
       now - base::TimeDelta::FromDays(FOUR_WEEKS_IN_DAYS);
 
   for (const auto& origin_to_count : remaining_origins) {
     GURL origin = origin_to_count.first;
     // It appears that the history service occasionally sends bad URLs to us.
@@ skipping 23 matching lines @@
     // in the past, the next time the origin's engagement is accessed the
     // automatic decay will kick in - i.e. a double decay will have occurred.
     // To prevent this, compute the decay that would have taken place since the
     // new last visit and add it to the engagement at this point. When the
     // engagement is next accessed, it will decay back to the proportionally
     // reduced value rather than being decayed once here, and then once again
     // when it is next accessed.
     int undecay = 0;
     int days_since_engagement = (now - last_visit).InDays();
     if (days_since_engagement > 0) {
-      int periods = days_since_engagement /
-                    SiteEngagementScore::GetDecayPeriodInDays();
+      int periods =
+          days_since_engagement / SiteEngagementScore::GetDecayPeriodInDays();
       undecay = periods * SiteEngagementScore::GetDecayPoints();
     }
 
     SiteEngagementScore engagement_score = CreateEngagementScore(origin);
 
     double score = std::min(
         SiteEngagementScore::kMaxPoints,
         (proportion_remaining * engagement_score.GetScore()) + undecay);
     engagement_score.Reset(score, last_visit);
-    if (!engagement_score.last_shortcut_launch_time().is_null()
-        && engagement_score.last_shortcut_launch_time() > last_visit) {
+    if (!engagement_score.last_shortcut_launch_time().is_null() &&
+        engagement_score.last_shortcut_launch_time() > last_visit) {
       engagement_score.set_last_shortcut_launch_time(last_visit);
     }
 
     engagement_score.Commit();
   }
 }