Add histogram for "scan credit card" usage.

components/autofill/core/browser/autofill_metrics.h

 // Copyright 2013 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_AUTOFILL_CORE_BROWSER_AUTOFILL_METRICS_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_METRICS_H_
 
 #include <stddef.h>
 #include <string>
 
@@ skipping 177 matching lines @@
     // Our heuristics detected at least one auto-fillable field, and the server
     // response overrode the type of at least one field.
     QUERY_RESPONSE_OVERRODE_LOCAL_HEURISTICS,
 
     // Our heuristics did not detect any auto-fillable fields, but the server
     // response did detect at least one.
     QUERY_RESPONSE_WITH_NO_LOCAL_HEURISTICS,
     NUM_SERVER_QUERY_METRICS,
   };
 
+  // Logs usage of "Scan card" control item.
+  enum ScanCreditCardPromptMetric {
+    // "Scan card" was presented to the user.
+    SCAN_CARD_ITEM_SHOWN,
+    // "Scan card" was selected by the user.
+    SCAN_CARD_ITEM_SELECTED,
+    // The user selected something in the dropdown besides "scan card".
+    SCAN_CARD_OTHER_ITEM_SELECTED,
+    NUM_SCAN_CREDIT_CARD_PROMPT_METRICS,
+  };
+
   // Each of these metrics is logged only for potentially autofillable forms,
   // i.e. forms with at least three fields, etc.
   // These are used to derive certain "user happiness" metrics.  For example, we
   // can compute the ratio (USER_DID_EDIT_AUTOFILLED_FIELD / USER_DID_AUTOFILL)
   // to see how often users have to correct autofilled data.
   enum UserHappinessMetric {
     // Loaded a page containing forms.
     FORMS_LOADED,
     // Submitted a fillable form -- i.e. one with at least three field values
     // that match the user's stored Autofill data -- and all matching fields
@@ skipping 96 matching lines @@
     VERIFY_CVV,
     INVALID_FORM_FIELD,
     REQUIRE_PHONE_NUMBER,
     NUM_WALLET_REQUIRED_ACTIONS
   };
 
   AutofillMetrics();
   virtual ~AutofillMetrics();
 
   static void LogCreditCardInfoBarMetric(InfoBarMetric metric);
+  static void LogScanCreditCardPromptMetric(ScanCreditCardPromptMetric metric);
 
   virtual void LogDeveloperEngagementMetric(
       DeveloperEngagementMetric metric) const;
 
   virtual void LogHeuristicTypePrediction(FieldTypeQualityMetric metric,
                                           ServerFieldType field_type) const;
   virtual void LogOverallTypePrediction(FieldTypeQualityMetric metric,
                                         ServerFieldType field_type) const;
   virtual void LogServerTypePrediction(FieldTypeQualityMetric metric,
                                        ServerFieldType field_type) const;
@@ skipping 83 matching lines @@
   // form.
   virtual void LogAddressSuggestionsCount(size_t num_suggestions) const;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AutofillMetrics);
 };
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_METRICS_H_