PaymentHandler: Implement PaymentInstruments.clear().

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 9219e0bfb71cbb0b9777ed96bf304a4891cd5b1b..9155f4f8c5748090c44ae8487cb4e7775390208d 100644
--- a/content/browser/payments/payment_app_database.h
+++ b/content/browser/payments/payment_app_database.h
@@ -44,6 +44,8 @@ class CONTENT_EXPORT PaymentAppDatabase {
       base::OnceCallback<void(payments::mojom::PaymentHandlerStatus)>;
   using WritePaymentInstrumentCallback =
       base::OnceCallback<void(payments::mojom::PaymentHandlerStatus)>;
+  using ClearPaymentInstrumentsCallback =
+      base::OnceCallback<void(payments::mojom::PaymentHandlerStatus)>;
 
   explicit PaymentAppDatabase(
       scoped_refptr<ServiceWorkerContextWrapper> service_worker_context);
@@ -69,6 +71,8 @@ class CONTENT_EXPORT PaymentAppDatabase {
                               const std::string& instrument_key,
                               payments::mojom::PaymentInstrumentPtr instrument,
                               WritePaymentInstrumentCallback callback);
+  void ClearPaymentInstruments(const GURL& scope,
+                               ClearPaymentInstrumentsCallback callback);
 
  private:
   // WriteManifest callbacks
@@ -150,6 +154,20 @@ class CONTENT_EXPORT PaymentAppDatabase {
   void DidWritePaymentInstrument(WritePaymentInstrumentCallback callback,
                                  ServiceWorkerStatusCode status);
 
+  // ClearPaymentInstruments callbacks

[please use gerrit instead, 2017/05/02 20:08:12]

Wouldn't it be simpler to have one call with one callback instead of this
bouncing around?

[zino, 2017/05/03 14:50:00]

Sorry, I don't understand your words fully.

If you'd like to call service_worker_context_->ClearRegistrationUserData()
without calling KeysOfPaymentInstruments, it's possible but we should add a new
API in service_worker directory.
But I thought that adding new APIs should be minimized if possible. (Moreover
this is not performance sensitive feature.)

+  void DidFindRegistrationToClearPaymentInstruments(
+      const GURL& scope,
+      ClearPaymentInstrumentsCallback callback,
+      ServiceWorkerStatusCode status,
+      scoped_refptr<ServiceWorkerRegistration> registration);
+  void DidGetKeysToClearPaymentInstruments(
+      int64_t registration_id,
+      ClearPaymentInstrumentsCallback callback,
+      const std::vector<std::string>& keys,
+      payments::mojom::PaymentHandlerStatus status);
+  void DidClearPaymentInstruments(ClearPaymentInstrumentsCallback callback,
+                                  ServiceWorkerStatusCode status);
+
   scoped_refptr<ServiceWorkerContextWrapper> service_worker_context_;
   base::WeakPtrFactory<PaymentAppDatabase> weak_ptr_factory_;