[Payments] Add PaymentRequest checkout funnel UKMs.

components/payments/core/journey_logger.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_PAYMENTS_CORE_JOURNEY_LOGGER_H_
 #define COMPONENTS_PAYMENTS_CORE_JOURNEY_LOGGER_H_
 
 #include <string>
 
 #include "base/macros.h"
+#include "url/gurl.h"
+
+namespace ukm {
+class UkmService;
+}
+
+namespace internal {
+// Name constants are exposed here so they can be referenced from tests.
+extern const char kUKMCheckoutFunnelEntryName[];
+extern const char kUKMCompletionStatusMetricName[];
+extern const char kUKMLastStepMetricName[];
+}  // namespace internal
 
 namespace payments {
 
 // A class to keep track of different stats during a Payment Request journey. It
 // collects different metrics during the course of the checkout flow, like the
 // number of credit cards that the user added or edited. The metrics will be
 // logged when RecordJourneyStatsHistograms is called with the completion status
 // of the Payment Request.
 class JourneyLogger {
  public:
@@ skipping 18 matching lines @@
 
   // Used to log different parameters' effect on whether the transaction was
   // completed.
   enum CompletionStatus {
     COMPLETION_STATUS_COMPLETED = 0,
     COMPLETION_STATUS_USER_ABORTED = 1,
     COMPLETION_STATUS_OTHER_ABORTED = 2,
     COMPLETION_STATUS_MAX,
   };
 
+  // The steps of a successful Payment Request.
+  enum CompletionStep {

[Mathieu, 2017/04/10 01:03:02]

Completion is misleading, let's find a better term

[sebsg, 2017/04/10 15:30:28]

Done.

+    STEP_INITIATED = 0,

[Mathieu, 2017/04/10 01:03:02]

had an idea, let me know what you think.

if each value was 1 << 0, 1 << 1, etc., we could accumulate 

checkout_step_ |= step;

And this would allow us to log various other steps (not necessarily linear)
easily. 

Let's say I extend your example and we have

SELECTED_SHIPPING_OPTION = 1 << 4
SELECTED_PAYMENT_METHOD = 1 << 5
etc.

we could de facto differentiate in the metrics between 
00111 and 11111 or 10111, which are all success cases but with variations.

[sebsg, 2017/04/10 15:30:29]

Excellent idea! I was thinking that we should add more stuff, like added card or
something. This is perfect!

+    STEP_SHOWN = 1,
+    STEP_PAY_CLICKED = 2,
+    STEP_RECEIVED_INSTRUMENT_DETAILS = 3,

[Mathieu, 2017/04/10 01:03:02]

I would recommend removing the STEP_ prefix from all these

[sebsg, 2017/04/10 15:30:28]

Acknowledged.

+    STEP_MAX,
+  };
+
   // Used to mesure the impact of the CanMakePayment return value on whether the
   // Payment Request is shown to the user.
   static const int CMP_SHOW_COULD_NOT_MAKE_PAYMENT_AND_DID_NOT_SHOW = 0;
   static const int CMP_SHOW_DID_SHOW = 1 << 0;
   static const int CMP_SHOW_COULD_MAKE_PAYMENT = 1 << 1;
   static const int CMP_SHOW_MAX = 4;
 
-  explicit JourneyLogger(bool is_incognito);
+  explicit JourneyLogger(bool is_incognito,

[Mathieu, 2017/04/10 01:03:02]

no explicit

[sebsg, 2017/04/10 15:30:28]

Done.

[sebsg, 2017/04/10 15:30:29]

Done.

+                         GURL url,
+                         ukm::UkmService* ukm_service);
   ~JourneyLogger();
 
   // Increments the number of selection adds for the specified section.
   void IncrementSelectionAdds(Section section);
 
   // Increments the number of selection changes for the specified section.
   void IncrementSelectionChanges(Section section);
 
   // Increments the number of selection edits for the specified section.
   void IncrementSelectionEdits(Section section);
 
   // Sets the number of suggestions shown for the specified section.
   void SetNumberOfSuggestionsShown(Section section, int number);
 
   // Records the fact that the merchant called CanMakePayment and records it's
   // return value.
   void SetCanMakePaymentValue(bool value);
 
   // Records the fact that the Payment Request was shown to the user.
   void SetShowCalled();
 
+  // Records the steps as they are done.
+  void SetCurrentStep(CompletionStep step);
+
   // Records the histograms for all the sections that were requested by the
   // merchant and for the usage of the CanMakePayment method and its effect on
   // the transaction. This method should be called when the Payment Request has
   // either been completed or aborted.
   void RecordJourneyStatsHistograms(CompletionStatus completion_status);
 
  private:
   static const int NUMBER_OF_SECTIONS = 3;
 
   // Note: These constants should always be in sync with their counterpart in
@@ skipping 30 matching lines @@
 
   // Records CanMakePayment's return value effect on whether the Payment Request
   // was shown or not.
   void RecordCanMakePaymentEffectOnShow();
 
   // Records the completion status depending on the the usage and return value
   // of the CanMakePaymentMethod.
   void RecordCanMakePaymentEffectOnCompletion(
       CompletionStatus completion_status);
 
+  // Records the Payment Request Url Keyed Metrics.
+  void RecordUkms(CompletionStatus completion_status);

[Mathieu, 2017/04/10 01:03:02]

RecordUrlKeyedMetrics is nice and descriptive

[sebsg, 2017/04/10 15:30:29]

Done.

+
   SectionStats sections_[NUMBER_OF_SECTIONS];
   bool was_can_make_payments_used_;
   bool could_make_payment_;
   bool was_show_called_;
   bool is_incognito_;
 
+  CompletionStep current_step_;
+
+  // For the UKMs.

[Mathieu, 2017/04/10 01:03:02]

nit: I don't think we need this line

[sebsg, 2017/04/10 15:30:28]

Done.

[sebsg, 2017/04/10 15:30:29]

Done.

+  GURL url_;
+  ukm::UkmService* ukm_service_;
+
   DISALLOW_COPY_AND_ASSIGN(JourneyLogger);
 };
 
 }  // namespace payments
 
 #endif  // COMPONENTS_PAYMENTS_CORE_JOURNEY_LOGGER_H_