Separate tracking for profiles that haven't been accessed in 4 weeks.

chrome/browser/profiles/profile_metrics.cc

Index: chrome/browser/profiles/profile_metrics.cc
diff --git a/chrome/browser/profiles/profile_metrics.cc b/chrome/browser/profiles/profile_metrics.cc
index bd4ac3b248a3ddd656b8946f1e09e5254e7ac4dc..2b68860e6ee2ddf77fbd00c82ff3cf1f1abc04c6 100644
--- a/chrome/browser/profiles/profile_metrics.cc
+++ b/chrome/browser/profiles/profile_metrics.cc
@@ -19,13 +19,15 @@
 namespace {
 
 const int kMaximumReportedProfileCount = 5;
+const int kMaximumDaysOfDisuse = 4 * 7;  // Should be integral number of weeks.
 
 struct ProfileCounts {
   size_t total;
   size_t signedin;
   size_t managed;
+  size_t unused;
 
-  ProfileCounts() : total(0), signedin(0), managed(0) {}
+  ProfileCounts() : total(0), signedin(0), managed(0), unused(0) {}
 };
 
 ProfileMetrics::ProfileType GetProfileType(
@@ -59,11 +61,19 @@ bool CountProfileInformation(ProfileManager* manager, ProfileCounts* counts) {
   if (!number_of_profiles)
     return false;
 
+  // Maximum age for "active" profile is 4 weeks.
+  base::Time oldest = base::Time::Now() -
+      base::TimeDelta::FromDays(kMaximumDaysOfDisuse);
+
   for (size_t i = 0; i < number_of_profiles; ++i) {
-    if (info_cache.ProfileIsManagedAtIndex(i))
-      counts->managed++;
-    if (!info_cache.GetUserNameOfProfileAtIndex(i).empty())
-      counts->signedin++;
+    if (info_cache.GetProfileActiveTimeAtIndex(i) < oldest) {

[rpetterson, 2014/01/22 21:40:27]

Overall I think this is an interesting metric to record. My only question is
whether you want to not record the other metrics if it is unused. Would it
better to know that I've got 10 managed profiles, 9 signed in profiles and 3 of
those unused? Would we want to know if the unused profiles were also managed
and/or signed in?

[bcwhite, 2014/01/23 14:07:38]

From the point-of-view of "signed in" tracking, we wanted to be able to discount
profiles that were created and never used, as frequently happens when people are
experimenting.

I think if we wanted the detail you mention, we'd have to duplicate all the
stats: managed, managed_unused, signedin, signedin_unused, total, total_unused. 
Otherwise, when looking at stats you'd have no idea if it was the signed-in &
managed profiles that were unused or the opposite.

+      counts->unused++;
+    } else {
+      if (info_cache.ProfileIsManagedAtIndex(i))
+        counts->managed++;
+      if (!info_cache.GetUserNameOfProfileAtIndex(i).empty())
+        counts->signedin++;
+    }
   }
   return true;
 }
@@ -130,6 +140,8 @@ void ProfileMetrics::LogNumberOfProfiles(ProfileManager* manager) {
                              100 * counts.managed / counts.total);
     UMA_HISTOGRAM_COUNTS_100("Profile.NumberOfSignedInProfiles",
                              counts.signedin);
+    UMA_HISTOGRAM_COUNTS_100("Profile.NumberOfUnusedProfiles",
+                             counts.unused);
 
     UpdateReportedOSProfileStatistics(counts.total, counts.signedin);
   }