[Payments] Add validation for unsupported credit card types in editor.

components/autofill/core/browser/validation.h

Index: components/autofill/core/browser/validation.h
diff --git a/components/autofill/core/browser/validation.h b/components/autofill/core/browser/validation.h
index 88db88bbc35fae6808cb92c30ed199e2a1538e28..0b496e2b950aa933706e6b6699d4205ba30bf644 100644
--- a/components/autofill/core/browser/validation.h
+++ b/components/autofill/core/browser/validation.h
@@ -30,11 +30,19 @@ bool IsValidCreditCardNumber(const base::string16& text);
 bool IsValidCreditCardSecurityCode(const base::string16& code,
                                    const base::StringPiece card_type);
 
+// Returns true if |text| is a supported card type and a valid credit card
+// number. |error_message| can't be null and will be filled with the appropriate
+// error message.
+bool IsValidCreditCardNumberForBasicCardNetworks(
+    const base::string16& text,
+    const std::set<std::string>& supported_basic_card_networks,
+    base::string16* error_message);
+
 // Returns true if |text| looks like a valid e-mail address.
 bool IsValidEmailAddress(const base::string16& text);
 
-// Returns true if |text| is a valid US state name or abbreviation.  It is
-// case insensitive.  Valid for US states only.
+// Returns true if |text| is a valid US state name or abbreviation.  It is case
+// insensitive.  Valid for US states only.
 bool IsValidState(const base::string16& text);
 
 // Returns true if |text| looks like a valid zip code.