PaymentHandler: Implement PaymentInstruments.delete().

third_party/WebKit/LayoutTests/http/tests/payments/payment-instruments.html

Index: third_party/WebKit/LayoutTests/http/tests/payments/payment-instruments.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/payments/payment-instruments.html b/third_party/WebKit/LayoutTests/http/tests/payments/payment-instruments.html
index e52f67ec927f7723824fac31634605694e9b0d84..7f6c7fbf89d00e5cf05cd1e69c2f9616d6b2b6d4 100644
--- a/third_party/WebKit/LayoutTests/http/tests/payments/payment-instruments.html
+++ b/third_party/WebKit/LayoutTests/http/tests/payments/payment-instruments.html
@@ -45,4 +45,41 @@ promise_test(test => {
       .catch(unreached_rejection(test));
   }, 'PaymentInstruments set/get methods test');
 
+promise_test(test => {
+    var registration;
+    var script_url = 'resources/empty-worker.js';
+    var scope = 'resources/';
+
+    return service_worker_unregister_and_register(test, script_url, scope)
+      .then(r => {
+          registration = r;
+          return wait_for_state(test, registration.installing, 'activated');
+        })
+      .then(state => {
+          assert_equals(state, 'activated');
+          return registration.paymentManager.instruments.set(
+              'test_key',
+              {
+                name: 'Visa ending ****4756',
+                enabledMethods: ['basic-card'],
+                capabilities: {
+                  supportedNetworks: ['visa'],
+                  supportedTypes: ['credit']
+                }
+              });
+        })
+      .then(result => {
+          assert_equals(result, undefined);
+          return registration.paymentManager.instruments.delete('test_key');
+        })
+      .then(result => {
+          assert_equals(result, true);
+          return registration.paymentManager.instruments.delete('test_key');
+        })
+      .then(result => {
+          assert_equals(result, false);
+        })
+      .catch(unreached_rejection(test));
+  }, 'PaymentInstruments delete method test');
+
 </script>