PaymentHandler: Implement GetAllPaymentApps().

content/browser/payments/payment_app_provider_impl.h

Index: content/browser/payments/payment_app_provider_impl.h
diff --git a/content/browser/payments/payment_app_provider_impl.h b/content/browser/payments/payment_app_provider_impl.h
index a4b8278f99068c2dd37d1355328d9cce53e4b22c..1de4b9453d5ed8263c50e2675a27a856178a9a1b 100644
--- a/content/browser/payments/payment_app_provider_impl.h
+++ b/content/browser/payments/payment_app_provider_impl.h
@@ -20,6 +20,8 @@ class CONTENT_EXPORT PaymentAppProviderImpl : public PaymentAppProvider {
   // Should be accessed only on the UI thread.
   void GetAllManifests(BrowserContext* browser_context,
                        const GetAllManifestsCallback& callback) override;
+  void GetAllPaymentApps(BrowserContext* browser_context,
+                         GetAllPaymentAppsCallback callback) override;
   void InvokePaymentApp(BrowserContext* browser_context,
                         int64_t registration_id,
                         payments::mojom::PaymentAppRequestPtr app_request,