Add access count and time-since-accessed histograms to temp storage eviction.

storage/browser/quota/quota_manager.cc

Index: storage/browser/quota/quota_manager.cc
diff --git a/storage/browser/quota/quota_manager.cc b/storage/browser/quota/quota_manager.cc
index 0052f2d7ebf4f12662042e91b66a74bec1a82179..6d6872f44259495f1953a63c6cdba6e53bcd5e30 100644
--- a/storage/browser/quota/quota_manager.cc
+++ b/storage/browser/quota/quota_manager.cc
@@ -76,6 +76,10 @@ const int QuotaManager::kEvictionIntervalInMilliSeconds =
 
 const char QuotaManager::kTimeBetweenRepeatedOriginEvictionsHistogram[] =
     "Quota.TimeBetweenRepeatedOriginEvictions";
+const char QuotaManager::kEvictedOriginAccessedCountHistogram[] =
+    "Quota.EvictedOriginAccessCount";
+const char QuotaManager::kEvictedOriginTimeSinceAccessHistogram[] =
+    "Quota.EvictedOriginTimeSinceAccess";
 
 // Heuristics: assuming average cloud server allows a few Gigs storage
 // on the server side and the storage needs to be shared for user data
@@ -159,6 +163,18 @@ bool DeleteOriginInfoOnDBThread(const GURL& origin,
                                 bool is_eviction,
                                 QuotaDatabase* database) {
   DCHECK(database);
+
+  QuotaDatabase::OriginInfoTableEntry entry;
+
+  base::Time now = base::Time::Now();

[michaeln, 2015/10/30 00:49:02]

maybe swap  lines |now| and |entry| are declared on since entry is only used
within the new block below and now is used in the new block and in existing code
at the end of the method

[calamity, 2015/11/02 06:27:44]

Done.

+  if (database->GetOriginInfo(origin, type, &entry)) {

[michaeln, 2015/10/30 00:49:02]

please add |is_eviction| to this condition too

[calamity, 2015/11/02 06:27:44]

Done. Nice catch.

+    UMA_HISTOGRAM_COUNTS(QuotaManager::kEvictedOriginAccessedCountHistogram,
+                         entry.used_count);
+    UMA_HISTOGRAM_LONG_TIMES(
+        QuotaManager::kEvictedOriginTimeSinceAccessHistogram,
+        now - entry.last_access_time);
+  }
+
   if (!database->DeleteOriginInfo(origin, type))
     return false;
 
@@ -171,7 +187,6 @@ bool DeleteOriginInfoOnDBThread(const GURL& origin,
   if (!database->GetOriginLastEvictionTime(origin, type, &last_eviction_time))
     return false;
 
-  base::Time now = base::Time::Now();
   if (last_eviction_time != base::Time()) {
     UMA_HISTOGRAM_LONG_TIMES(
         QuotaManager::kTimeBetweenRepeatedOriginEvictionsHistogram,