PaymentHandler: Implement PaymentInstruments.keys().

content/browser/payments/payment_app_database.h

Index: content/browser/payments/payment_app_database.h
diff --git a/content/browser/payments/payment_app_database.h b/content/browser/payments/payment_app_database.h
index 2635d3877cf51485828331836d56f7470cefedb0..9219e0bfb71cbb0b9777ed96bf304a4891cd5b1b 100644
--- a/content/browser/payments/payment_app_database.h
+++ b/content/browser/payments/payment_app_database.h
@@ -37,6 +37,9 @@ class CONTENT_EXPORT PaymentAppDatabase {
   using ReadPaymentInstrumentCallback =
       base::OnceCallback<void(payments::mojom::PaymentInstrumentPtr,
                               payments::mojom::PaymentHandlerStatus)>;
+  using KeysOfPaymentInstrumentsCallback =
+      base::OnceCallback<void(const std::vector<std::string>&,
+                              payments::mojom::PaymentHandlerStatus)>;
   using HasPaymentInstrumentCallback =
       base::OnceCallback<void(payments::mojom::PaymentHandlerStatus)>;
   using WritePaymentInstrumentCallback =
@@ -57,6 +60,8 @@ class CONTENT_EXPORT PaymentAppDatabase {
   void ReadPaymentInstrument(const GURL& scope,
                              const std::string& instrument_key,
                              ReadPaymentInstrumentCallback callback);
+  void KeysOfPaymentInstruments(const GURL& scope,
+                                KeysOfPaymentInstrumentsCallback callback);
   void HasPaymentInstrument(const GURL& scope,
                             const std::string& instrument_key,
                             HasPaymentInstrumentCallback callback);
@@ -114,6 +119,15 @@ class CONTENT_EXPORT PaymentAppDatabase {
                                 const std::vector<std::string>& data,
                                 ServiceWorkerStatusCode status);
 
+  // KeysOfPaymentInstruments callbacks
+  void DidFindRegistrationToGetKeys(
+      KeysOfPaymentInstrumentsCallback callback,
+      ServiceWorkerStatusCode status,
+      scoped_refptr<ServiceWorkerRegistration> registration);
+  void DidGetKeysOfPaymentInstruments(KeysOfPaymentInstrumentsCallback callback,
+                                      const std::vector<std::string>& data,
+                                      ServiceWorkerStatusCode status);
+
   // HasPaymentInstrument callbacks
   void DidFindRegistrationToHasPaymentInstrument(
       const std::string& instrument_key,