Logs different SaveCardPrompt histogram names depending on if user

components/autofill/core/common/autofill_pref_names.h

Index: components/autofill/core/common/autofill_pref_names.h
diff --git a/components/autofill/core/common/autofill_pref_names.h b/components/autofill/core/common/autofill_pref_names.h
index cab272d6cb65cf9bc1fac1330f12161a9aead65b..e18a77abdb8db812630d45b04b81a04f6ada5856 100644
--- a/components/autofill/core/common/autofill_pref_names.h
+++ b/components/autofill/core/common/autofill_pref_names.h
@@ -11,6 +11,7 @@ namespace prefs {
 // Alphabetical list of preference names specific to the Autofill
 // component. Keep alphabetized, and document each in the .cc file.
 
+extern const char kAutofillAcceptSaveCreditCardPromptState[];
 extern const char kAutofillCreditCardSigninPromoImpressionCount[];
 extern const char kAutofillEnabled[];
 extern const char kAutofillProfileUseDatesFixed[];
@@ -18,6 +19,15 @@ extern const char kAutofillLastVersionDeduped[];
 extern const char kAutofillWalletImportEnabled[];
 extern const char kAutofillWalletImportStorageCheckboxState[];
 
+// Possible values for previous user decision when we displayed a save credit
+// card prompt.
+enum PreviousSaveCreditCardPromptUserDecision {
+  PREVIOUS_SAVE_CREDIT_CARD_PROMPT_USER_DECISION_NONE,
+  PREVIOUS_SAVE_CREDIT_CARD_PROMPT_USER_DECISION_ACCEPTED,
+  PREVIOUS_SAVE_CREDIT_CARD_PROMPT_USER_DECISION_DENIED,
+  NUM_PREVIOUS_SAVE_CREDIT_CARD_PROMPT_USER_DECISIONS
+};
+
 }  // namespace prefs
 }  // namespace autofill