[Autofill] Update credit card type detection logic.

components/autofill/core/browser/credit_card.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_CREDIT_CARD_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_CREDIT_CARD_H_
 
 #include <iosfwd>
 #include <string>
 #include <vector>
@@ skipping 19 matching lines @@
 
   // Returns a version of |number| that has any separator characters removed.
   static const base::string16 StripSeparators(const base::string16& number);
 
   // The user-visible type of the card, e.g. 'Mastercard'.
   static base::string16 TypeForDisplay(const std::string& type);
 
   // The ResourceBundle ID for the appropriate credit card image.
   static int IconResourceId(const std::string& type);
 
-  // The internal representation of credit card type.
+  // Returns the internal representation of credit card type corresponding to
+  // the given |number|.  The credit card type is determined purely according to
+  // the Issuer Identification Number (IIN), a.k.a. the "Bank Identification
+  // Number (BIN)", which is parsed from the relevant prefix of the |number|.
+  // This function performs no additional validation checks on the |number|.
+  // Hence, the returned type for both the valid card "4111-1111-1111-1111" and
+  // the invalid card "4garbage" will be Visa, which has an IIN of 4.
   static std::string GetCreditCardType(const base::string16& number);
 
   // FormGroup:
   virtual void GetMatchingTypes(const base::string16& text,
                                 const std::string& app_locale,
                                 FieldTypeSet* matching_types) const OVERRIDE;
   virtual base::string16 GetRawInfo(AutofillFieldType type) const OVERRIDE;
   virtual void SetRawInfo(AutofillFieldType type,
                           const base::string16& value) OVERRIDE;
   virtual base::string16 GetInfo(AutofillFieldType type,
@@ skipping 97 matching lines @@
 // So we can compare CreditCards with EXPECT_EQ().
 std::ostream& operator<<(std::ostream& os, const CreditCard& credit_card);
 
 // The string identifiers for credit card icon resources.
 extern const char* const kAmericanExpressCard;
 extern const char* const kDinersCard;
 extern const char* const kDiscoverCard;
 extern const char* const kGenericCard;
 extern const char* const kJCBCard;
 extern const char* const kMasterCard;
-extern const char* const kSoloCard;
 extern const char* const kVisaCard;
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_CREDIT_CARD_H_