[autofill] Add support for PSL domain matching for password autofill.

components/autofill/common/password_form_fill_data.h

Index: components/autofill/common/password_form_fill_data.h
diff --git a/components/autofill/common/password_form_fill_data.h b/components/autofill/common/password_form_fill_data.h
index 1c6091a80d0f43e19c8ac6a382be129a05606348..15e9ddbc6e6a5cdc8fdc8c91ba4768f70b5e12f7 100644
--- a/components/autofill/common/password_form_fill_data.h
+++ b/components/autofill/common/password_form_fill_data.h
@@ -25,10 +25,17 @@ struct UsernamesCollectionKey {
   base::string16 password;
 };
 
+struct PasswordAndRealm {
+  base::string16 password;
+  base::string16 realm;
+};
+
 // Structure used for autofilling password forms.
 // basic_data identifies the HTML form on the page and preferred username/
 //            password for login, while
-// additional_logins is a list of other matching user/pass pairs for the form.
+// preferred_realm the signon realm of the preferred user/pass pair.
+// additional_logins is a list of other matching username->PasswordAndRealm
+//                   pairs for the form.
 // other_possible_usernames is a list of possible usernames in the case where we
 //     aren't completely sure that the original saved username is correct.
 //     This data is keyed by the saved username/password to ensure uniqueness,
@@ -39,11 +46,12 @@ struct UsernamesCollectionKey {
 // associated with this form. This can happen, for example, if action URI's
 // of the observed form and our saved representation don't match up.
 struct PasswordFormFillData {
-  typedef std::map<base::string16, base::string16> LoginCollection;
+  typedef std::map<base::string16, PasswordAndRealm> LoginCollection;
   typedef std::map<UsernamesCollectionKey,
                    std::vector<base::string16> > UsernamesCollection;
 
   FormData basic_data;
+  base::string16 preferred_realm;
   LoginCollection additional_logins;
   UsernamesCollection other_possible_usernames;
   bool wait_for_username;