PaymentHandler: Implement PaymentInstruments.has().

content/browser/payments/payment_manager.cc

Index: content/browser/payments/payment_manager.cc
diff --git a/content/browser/payments/payment_manager.cc b/content/browser/payments/payment_manager.cc
index d8447f7facac34592089be94381de2321c0fb6ac..f1a9cc0f11d5a3bfcc1d2558562885279ae74d4a 100644
--- a/content/browser/payments/payment_manager.cc
+++ b/content/browser/payments/payment_manager.cc
@@ -76,6 +76,15 @@ void PaymentManager::SetPaymentInstrument(
       scope_, instrument_key, std::move(details), callback);
 }
 
+void PaymentManager::HasPaymentInstrument(
+    const std::string& instrument_key,
+    const HasPaymentInstrumentCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  payment_app_context_->payment_app_database()->HasPaymentInstrument(
+      scope_, instrument_key, callback);
+}
+
 void PaymentManager::GetPaymentInstrument(
     const std::string& instrument_key,
     const PaymentManager::GetPaymentInstrumentCallback& callback) {