Adds UKM for autofill attributes in form_structure.

components/autofill/core/browser/form_structure.cc

Index: components/autofill/core/browser/form_structure.cc
diff --git a/components/autofill/core/browser/form_structure.cc b/components/autofill/core/browser/form_structure.cc
index 02e861fe9c2a9a7076100f8dc5cd20968a3c1d6b..00b651082f6985721a2a2d2b5b6f2c2595bc6cc6 100644
--- a/components/autofill/core/browser/form_structure.cc
+++ b/components/autofill/core/browser/form_structure.cc
@@ -36,6 +36,7 @@
 #include "components/autofill/core/common/signatures_util.h"
 #include "components/rappor/public/rappor_utils.h"
 #include "components/rappor/rappor_service_impl.h"
+#include "components/ukm/ukm_service.h"
 
 namespace autofill {
 namespace {
@@ -332,7 +333,7 @@ FormStructure::FormStructure(const FormData& form)
 
 FormStructure::~FormStructure() {}
 
-void FormStructure::DetermineHeuristicTypes() {
+void FormStructure::DetermineHeuristicTypes(ukm::UkmService* ukm_service) {
   const auto determine_heuristic_types_start_time = base::TimeTicks::Now();
 
   // First, try to detect field types based on each field's |autocomplete|
@@ -363,6 +364,13 @@ void FormStructure::DetermineHeuristicTypes() {
     if (has_author_specified_types_) {
       AutofillMetrics::LogDeveloperEngagementMetric(
           AutofillMetrics::FILLABLE_FORM_CONTAINS_TYPE_HINTS);
+      AutofillMetrics::LogDeveloperEngagementUkm(
+          ukm_service, source_url(),
+          {AutofillMetrics::FILLABLE_FORM_CONTAINS_TYPE_HINTS,

[sebsg, 2017/03/29 13:52:58]

by looking at the comments of these constants, it seems that
FILLABLE_FOMR_CONTAINS_TYPE_HINTS is a superset of FILLABLE_FORM_PARSED.

https://cs.chromium.org/chromium/src/components/autofill/core/browser/autofil...

Do you think we could only log one? Maybe Math knows why it's logged this way
now?

That would remove the need to have multiple times the same metric in a
UKM_Entry, which is something I find a bit weird.

Thanks!

[csashi, 2017/03/29 16:15:11]

Yes, CONTAINS_TYPE_HINTS are a subset of FORM_PARSED. I am logging both to be
consistent with UMA metrics. If consistency with UMA is not important, I can log
just one.

BTW, the log schema seems to be specifically designed for multiple enums for the
same metric. See
https://codesearch.chromium.org/chromium/src/components/metrics/proto/ukm/ent...

[sebsg, 2017/03/29 17:55:13]

I see, I really prefer logging only once if it's a subset, since it's then
simpler to parse when analyzing the metrics. I just want to wait for Math to see
if he has another reason to keep them separated. I'll ping him :)

[sebsg, 2017/03/29 18:46:09]

Ok I talked with Math. Would you mind renaming the enum and changing the logic a
bit? The idea would be to make them mutually exclusive, so something like
FILLABLE_FORM_PARSED_WITH_HINTS and FILLABLE_FORM_PARSED_NO_HINT. WDYT?

[csashi, 2017/03/30 00:52:10]

Done.

+           AutofillMetrics::FILLABLE_FORM_PARSED});
+    } else {
+      AutofillMetrics::LogDeveloperEngagementUkm(
+          ukm_service, source_url(), {AutofillMetrics::FILLABLE_FORM_PARSED});
     }
   }