[Autofill] Log the number of profiles considered/removed during dedupe.

BUG=618356
TEST=PersonalDataManagerTest

Review-Url: https://codereview.chromium.org/2061303002
Cr-Commit-Position: refs/heads/master@{#399991}

components/autofill/core/browser/autofill_metrics.cc

@@ -594,6 +594,22 @@ void AutofillMetrics::LogParseFormTiming(const base::TimeDelta& duration) {
   UMA_HISTOGRAM_TIMES("Autofill.Timing.ParseForm", duration);
 }
 
+// static
+void AutofillMetrics::LogNumberOfProfilesConsideredForDedupe(
+    size_t num_considered) {
+  // A maximum of 50 is enforced to reduce the number of generated buckets.
+  UMA_HISTOGRAM_COUNTS_1000("Autofill.NumberOfProfilesConsideredForDedupe",
+                            std::min(int(num_considered), 50));
+}
+
+// static
+void AutofillMetrics::LogNumberOfProfilesRemovedDuringDedupe(
+    size_t num_removed) {
+  // A maximum of 50 is enforced to reduce the number of generated buckets.
+  UMA_HISTOGRAM_COUNTS_1000("Autofill.NumberOfProfilesRemovedDuringDedupe",
+                            std::min(int(num_removed), 50));
+}
+
 AutofillMetrics::FormEventLogger::FormEventLogger(bool is_for_credit_card)
     : is_for_credit_card_(is_for_credit_card),
       is_server_data_available_(false),

components/autofill/core/browser/autofill_metrics.h

@@ -639,6 +639,12 @@ class AutofillMetrics {
   // This should be called when parsing each form.
   static void LogParseFormTiming(const base::TimeDelta& duration);
 
+  // Log how many profiles were considered for the deduplication process.
+  static void LogNumberOfProfilesConsideredForDedupe(size_t num_considered);
+
+  // Log how many profiles were removed as part of the deduplication process.
+  static void LogNumberOfProfilesRemovedDuringDedupe(size_t num_removed);
+
   // Utility to autofill form events in the relevant histograms depending on
   // the presence of server and/or local data.
   class FormEventLogger {

components/autofill/core/browser/personal_data_manager.cc

@@ -1563,6 +1563,8 @@ void PersonalDataManager::FindAndMergeDuplicateProfiles(
     const std::vector<AutofillProfile*>& existing_profiles,
     AutofillProfile* profile_to_merge,
     std::vector<std::string>* profile_guids_to_delete) {
+  AutofillMetrics::LogNumberOfProfilesConsideredForDedupe(
+      existing_profiles.size());
   for (AutofillProfile* existing_profile : existing_profiles) {
     // Don't try to merge a profile with itself or with any profile with a
     // different PrimaryValue.
@@ -1583,6 +1585,9 @@ void PersonalDataManager::FindAndMergeDuplicateProfiles(
       }
     }
   }
+
+  AutofillMetrics::LogNumberOfProfilesRemovedDuringDedupe(
+      profile_guids_to_delete->size());
 }
 
 }  // namespace autofill

components/autofill/core/browser/personal_data_manager_unittest.cc

@@ -21,6 +21,7 @@
 #include "base/metrics/field_trial.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/waitable_event.h"
+#include "base/test/histogram_tester.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
@@ -4451,6 +4452,7 @@ TEST_F(PersonalDataManagerTest, DedupeOnInsert) {
                        "homer.simpson@abc.com", "", "742. Evergreen Terrace",
                        "", "Springfield", "IL", "91601", "US", "12345678910");
 
+  base::HistogramTester histogram_tester;
   // Save the imported profile (use it).
   personal_data_->SaveImportedProfile(imported_profile);
 
@@ -4463,6 +4465,12 @@ TEST_F(PersonalDataManagerTest, DedupeOnInsert) {
   // The imported profile and saved profiles 1 and 2 should be merged together.
   // Therefore there should only be 3 saved profiles.
   ASSERT_EQ(3U, profiles.size());
+  // 4 profiles were considered for dedupe.
+  histogram_tester.ExpectUniqueSample(
+      "Autofill.NumberOfProfilesConsideredForDedupe", 4, 1);
+  // 1 profile was removed.
+  histogram_tester.ExpectUniqueSample(
+      "Autofill.NumberOfProfilesRemovedDuringDedupe", 1, 1);
 
   // Sort the profiles by frecency to have a deterministic order.
   base::Time comparison_time = base::Time::Now();
@@ -4542,9 +4550,16 @@ TEST_F(PersonalDataManagerTest,
   existing_profiles.push_back(&profile4);
   existing_profiles.push_back(&profile5);
 
+  base::HistogramTester histogram_tester;
   std::vector<std::string> guids_to_delete;
   personal_data_->FindAndMergeDuplicateProfiles(existing_profiles, &profile1,
                                                 &guids_to_delete);
+  // 5 profiles were considered for dedupe.
+  histogram_tester.ExpectUniqueSample(
+      "Autofill.NumberOfProfilesConsideredForDedupe", 5, 1);
+  // 2 profiles were removed.
+  histogram_tester.ExpectUniqueSample(
+      "Autofill.NumberOfProfilesRemovedDuringDedupe", 2, 1);
 
   // Profile1 should be deleted because it was sent as the profile to merge and
   // thus was merged into profile3 and then into profile5.
@@ -4602,6 +4617,7 @@ TEST_F(PersonalDataManagerTest,
                        "homer.simpson@abc.com", "", "742. Evergreen Terrace",
                        "", "Springfield", "IL", "91601", "US", "");
 
+  base::HistogramTester histogram_tester;
   personal_data_->SaveImportedProfile(imported_profile);
 
   EXPECT_CALL(personal_data_observer_, OnPersonalDataChanged())
@@ -4613,6 +4629,12 @@ TEST_F(PersonalDataManagerTest,
   // The imported profile and saved profiles 1 and 2 should be merged together.
   // Therefore there should only be 1 saved profile.
   ASSERT_EQ(1U, profiles.size());
+  // 2 profiles were considered for dedupe.
+  histogram_tester.ExpectUniqueSample(
+      "Autofill.NumberOfProfilesConsideredForDedupe", 2, 1);
+  // 1 profile was removed.
+  histogram_tester.ExpectUniqueSample(
+      "Autofill.NumberOfProfilesRemovedDuringDedupe", 1, 1);
 
   // Since profiles with higher frecency scores are merged into profiles with
   // lower frecency scores, the result of the merge should be contained in

tools/metrics/histograms/histograms.xml

@@ -2849,6 +2849,20 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Autofill.NumberOfProfilesConsideredForDedupe" units="profiles">
+  <owner>mathp@chromium.org</owner>
+  <summary>
+    The number of Autofill profiles that have been considered for deduplication.
+  </summary>
+</histogram>
+
+<histogram name="Autofill.NumberOfProfilesRemovedDuringDedupe" units="profiles">
+  <owner>mathp@chromium.org</owner>
+  <summary>
+    The number of Autofill profiles that have been removed during deduplication.
+  </summary>
+</histogram>
+
 <histogram name="Autofill.PasswordFormQueryVolume"
     enum="PasswordFormQueryVolume">
   <owner>dvadym@chromium.org</owner>