[autofill] Expand Autofill.Quality.* to log false positives/true negatives.

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 244 matching lines @@
     // the prompt was showing.
     SAVE_CARD_PROMPT_END_NAVIGATION_SHOWING,
     // The prompt and icon were removed  because of navigation away from the
     // page that caused the prompt to be shown. The navigation occurred while
     // the prompt was hidden.
     SAVE_CARD_PROMPT_END_NAVIGATION_HIDDEN,
     // The prompt was dismissed because the user clicked the "Learn more" link.
     SAVE_CARD_PROMPT_DISMISS_CLICK_LEARN_MORE,
     // The prompt was dismissed because the user clicked a legal message link.
     SAVE_CARD_PROMPT_DISMISS_CLICK_LEGAL_MESSAGE,
+
     NUM_SAVE_CARD_PROMPT_METRICS,
   };
 
   // Metrics measuring how well we predict field types.  Exactly three such
   // metrics are logged for each fillable field in a submitted form: for
   // the heuristic prediction, for the crowd-sourced prediction, and for the
   // overall prediction.
   enum FieldTypeQualityMetric {
-    TYPE_UNKNOWN = 0,  // Offered no prediction.
-    TYPE_MATCH,        // Predicted correctly.
-    TYPE_MISMATCH,     // Predicted incorrectly.
+    // The field was found to be of type T, but autofill made no prediction.
+    TYPE_UNKNOWN = 0,
+    // The field was found to be of type T, which matches the predicted type.
+    TYPE_MATCH,
+    // The field was found to be of type T, autofill predicted some other type.
+    TYPE_MISMATCH,
+    // The field was left empty and autofil predicted that the field type would
+    // be UNKNOWN.
+    TYPE_MATCH_EMPTY,
+    // The field was populated with data that did not match any part of the
+    // user's profile (it's type could not be determined). Autofill predicted
+    // the field's type would be UNKNOWN.
+    TYPE_MATCH_UNKNOWN,
+    // The field was left empty, autofill predicted the user would populate it
+    // with autofillable data.
+    TYPE_MISMATCH_EMPTY,
+    // The field was populated with data that did not match any part of the
+    // user's profile (it's type could not be determined). Autofill predicted
+    // the user would populate it with autofillable data.
+    TYPE_MISMATCH_UNKNOWN,
+    // This must be the last value.
     NUM_FIELD_TYPE_QUALITY_METRICS,
   };
 
   enum QualityMetricType {
     TYPE_SUBMISSION = 0,      // Logged based on user's submitted data.
     TYPE_NO_SUBMISSION,       // Logged based on user's entered data.
     TYPE_AUTOCOMPLETE_BASED,  // Logged based on the value of autocomplete attr.
     NUM_QUALITY_METRIC_TYPES,
   };
 
@@ skipping 487 matching lines @@
     FormFieldData last_polled_field_;
   };
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(AutofillMetrics);
 };
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_METRICS_H_