Collecting UMA metrics for the UnmaskPrompt.

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 78540dc4127fcf47760472d4b5302386781ac989..52d64755d69b79ce7f754e2c64f2083978b32b5b 100644
--- a/components/autofill/core/browser/autofill_metrics.h
+++ b/components/autofill/core/browser/autofill_metrics.h
@@ -284,6 +284,34 @@ class AutofillMetrics {
     NUM_FORM_EVENTS,
   };
 
+  // Events related to the Unmask Credit Card Prompt.
+  enum UnmaskPromptEvent {
+    // The prompt was shown.
+    UNMASK_PROMPT_SHOWN = 0,
+    // The prompt was closed without attempting to unmask the card.
+    UNMASK_PROMPT_CLOSED_NO_ATTEMPTS,
+    // The prompt was closed without unmasking the card, but with at least
+    // one attempt.
+    UNMASK_PROMPT_CLOSED_FAILED_TO_UNMASK,
+    // Successfully unmasked the card.
+    UNMASK_PROMPT_UNMASKED_CARD,
+    // Saved the card locally (masked card was upgraded to a full card).
+    UNMASK_PROMPT_SAVED_CARD_LOCALLY,
+    // User chose to opt in (checked the checkbox when it was empty).
+    // Only logged if there was an attempt to unmask.
+    UNMASK_PROMPT_LOCAL_SAVE_DID_OPT_IN,
+    // User kept opt in (left the checkbox checked).
+    // Only logged if there was an attempt to unmask.
+    UNMASK_PROMPT_LOCAL_SAVE_KEPT_OPT_IN,

[Evan Stade, 2015/03/17 01:49:15]

this name doesn't quite make sense to me. You can't keep opted in. It's more
like "didn't opt out".

[Walter Cacau, 2015/03/18 01:27:43]

Done.

+    // User chose to opt out (unchecked the checkbox when it was check).
+    // Only logged if there was an attempt to unmask.
+    UNMASK_PROMPT_LOCAL_SAVE_DID_OPT_OUT,
+    // User kept opt opt (left the checkbox unchecked).
+    // Only logged if there was an attempt to unmask.
+    UNMASK_PROMPT_LOCAL_SAVE_KEPT_OPT_OUT,
+    NUM_UNMASK_PROMT_EVENTS,
+  };
+
   // For measuring the network request time of various Wallet API calls. See
   // WalletClient::RequestType.
   enum WalletApiCallMetric {
@@ -410,6 +438,9 @@ class AutofillMetrics {
   // Logs |event| to the UI events histogram.
   static void LogDialogUiEvent(DialogUiEvent event);
 
+  // Logs |event| to the unmask prompt events histogram.
+  static void LogUnmaskPromptEvent(UnmaskPromptEvent event);
+
   // Logs |metric| to the Wallet errors histogram.
   static void LogWalletErrorMetric(WalletErrorMetric metric);