UKM that threads together multiple form interaction events.

components/autofill/core/browser/autofill_metrics.h

Index: components/autofill/core/browser/autofill_metrics.h
diff --git a/components/autofill/core/browser/autofill_metrics.h b/components/autofill/core/browser/autofill_metrics.h
index 15ee9a173c9debb9119f586cc6c5ce5773b62a2e..33341c454c2c0b1d9caf09903836a27200bf20a3 100644
--- a/components/autofill/core/browser/autofill_metrics.h
+++ b/components/autofill/core/browser/autofill_metrics.h
@@ -7,18 +7,17 @@
 
 #include <stddef.h>
 #include <string>
+#include <utility>
+#include <vector>
 
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "components/autofill/core/browser/autofill_client.h"
 #include "components/autofill/core/browser/autofill_profile.h"
 #include "components/autofill/core/browser/credit_card.h"
 #include "components/autofill/core/browser/field_types.h"
 #include "components/autofill/core/common/form_field_data.h"
 
-namespace base {
-class TimeDelta;
-}  // namespace base
-
 namespace ukm {
 class UkmService;
 }  // namespace ukm
@@ -29,6 +28,17 @@ extern const char kUKMCardUploadDecisionEntryName[];
 extern const char kUKMCardUploadDecisionMetricName[];
 extern const char kUKMDeveloperEngagementEntryName[];
 extern const char kUKMDeveloperEngagementMetricName[];
+
+// Each form interaction event has a separate |UkmEntry|.
+// Each |UkmEntry| has 2 metrics:
+// 1. The value of the corresponding enum (e.g. value of |UserHappiness|).
+// 2. Time elapsed, in milliseconds, since we loaded the form.
+extern const char kUKMAutofillFormSubmittedStateName[];
+extern const char kUKMUserHappinessMetricName[];
+extern const char kUKMAddressFormEventName[];
+extern const char kUKMCreditCardFormEventName[];
+extern const char kUKMUnmaskPromptEventName[];
+extern const char kUKMMillisecondsSinceFormLoadedMetricName[];
 }  // namespace internal
 
 namespace autofill {
@@ -543,6 +553,49 @@ class AutofillMetrics {
     NUM_CONVERTED_ADDRESS_CONVERSION_TYPES
   };
 
+  // Utility to log URL keyed |AutofillFormSubmittedState|,
+  // |UserHappinessMetric|, |FormEvent| and |UnmaskPromptEvent|.
+  class FormInteractionsUkmLogger {
+   public:
+    explicit FormInteractionsUkmLogger(ukm::UkmService* ukm_service);
+    ~FormInteractionsUkmLogger();
+
+    const GURL& url() const { return url_; }
+    void set_url(const GURL& url) { url_ = url; }
+    void set_form_loaded_timestamp(
+        const base::TimeTicks& form_loaded_timestamp) {
+      form_loaded_timestamp_ = form_loaded_timestamp;
+    }
+
+    // The following Log functions only log the form interactions to private
+    // class variables. |SubmitUkm| is the only method that calls the
+    // |UkmService|.
+    void LogAutofillFormSubmittedState(AutofillFormSubmittedState state);
+    void LogUserHappinessMetric(UserHappinessMetric metric);
+    void LogAddressFormEvent(FormEvent event);
+    void LogCreditCardFormEvent(FormEvent event);
+    void LogUnmaskPromptEvent(UnmaskPromptEvent event);
+
+    void SubmitUkm();
+
+   private:
+    struct Event {
+      Event(const char* const name, int value, const int64_t time_delta_millis)
+          : name(name), value(value), time_delta_millis(time_delta_millis) {}
+
+      const char* const name;
+      const int value;
+      const int64_t time_delta_millis;
+    };
+
+    void AddEvent(const char* const name, int value);
+
+    ukm::UkmService* ukm_service_;  // Weak reference.
+    base::TimeTicks form_loaded_timestamp_;
+    GURL url_;
+    std::vector<Event> events_;
+  };
+
   static void LogCardUploadDecisionMetric(CardUploadDecisionMetric metric);
   static void LogCreditCardInfoBarMetric(InfoBarMetric metric,
                                          bool is_uploading);
@@ -669,7 +722,9 @@ class AutofillMetrics {
 
   // This should be called at each form submission to indicate the autofilled
   // state of the form.
-  static void LogAutofillFormSubmittedState(AutofillFormSubmittedState state);
+  static void LogAutofillFormSubmittedState(
+      AutofillFormSubmittedState state,
+      FormInteractionsUkmLogger* form_interactions_ukm_logger);
 
   // This should be called when determining the heuristic types for a form's
   // fields.
@@ -708,20 +763,21 @@ class AutofillMetrics {
   static void LogDeveloperEngagementUkm(
       ukm::UkmService* ukm_service,
       const GURL& url,
-      AutofillMetrics::DeveloperEngagementMetric metric);
+      std::vector<AutofillMetrics::DeveloperEngagementMetric> metrics);
 
   // Logs the the |ukm_entry_name| with the specified |url| and the specified
   // |metrics|. Returns whether the ukm was sucessfully logged.
   static bool LogUkm(ukm::UkmService* ukm_service,
                      const GURL& url,
                      const std::string& ukm_entry_name,
-                     const std::map<std::string, int>& metrics);
+                     const std::vector<std::pair<const char*, int>>& metrics);
 
-  // Utility to autofill form events in the relevant histograms depending on
+  // Utility to log autofill form events in the relevant histograms depending on
   // the presence of server and/or local data.
   class FormEventLogger {
    public:
-    FormEventLogger(bool is_for_credit_card);
+    FormEventLogger(bool is_for_credit_card,
+                    FormInteractionsUkmLogger* form_interactions_ukm_logger);
 
     inline void set_is_server_data_available(bool is_server_data_available) {
       is_server_data_available_ = is_server_data_available;
@@ -754,7 +810,7 @@ class AutofillMetrics {
     void OnFormSubmitted();
 
    private:
-    void Log(FormEvent event) const;
+    void Log(FormEvent event, bool log_ukm) const;
 
     bool is_for_credit_card_;
     bool is_server_data_available_;
@@ -771,6 +827,9 @@ class AutofillMetrics {
 
     // The last field that was polled for suggestions.
     FormFieldData last_polled_field_;
+
+    FormInteractionsUkmLogger*
+        form_interactions_ukm_logger_;  // Weak reference.
   };
 
  private: