PaymentHandler: Implement PaymentInstruments.keys().

third_party/WebKit/Source/modules/payments/PaymentInstruments.cpp

Index: third_party/WebKit/Source/modules/payments/PaymentInstruments.cpp
diff --git a/third_party/WebKit/Source/modules/payments/PaymentInstruments.cpp b/third_party/WebKit/Source/modules/payments/PaymentInstruments.cpp
index 829a852b2c9f100a3642c7bbcf2f0f4106675b28..746145fa308068cbf8cc372bbb85aaf110dcf8e8 100644
--- a/third_party/WebKit/Source/modules/payments/PaymentInstruments.cpp
+++ b/third_party/WebKit/Source/modules/payments/PaymentInstruments.cpp
@@ -89,9 +89,20 @@ ScriptPromise PaymentInstruments::get(ScriptState* script_state,
   return promise;
 }
 
-ScriptPromise PaymentInstruments::keys() {
-  NOTIMPLEMENTED();
-  return ScriptPromise();
+ScriptPromise PaymentInstruments::keys(ScriptState* script_state) {
+  if (!manager_.is_bound()) {
+    return ScriptPromise::RejectWithDOMException(
+        script_state,
+        DOMException::Create(kInvalidStateError, kPaymentManagerUnavailable));
+  }
+
+  ScriptPromiseResolver* resolver = ScriptPromiseResolver::Create(script_state);
+  ScriptPromise promise = resolver->Promise();
+
+  manager_->KeysOfPaymentInstruments(ConvertToBaseCallback(
+      WTF::Bind(&PaymentInstruments::onKeysOfPaymentInstruments,
+                WrapPersistent(this), WrapPersistent(resolver))));
+  return promise;
 }
 
 ScriptPromise PaymentInstruments::has(ScriptState* script_state,
@@ -197,6 +208,16 @@ void PaymentInstruments::onGetPaymentInstrument(
   resolver->Resolve(instrument);
 }
 
+void PaymentInstruments::onKeysOfPaymentInstruments(
+    ScriptPromiseResolver* resolver,
+    const Vector<String>& keys,
+    payments::mojom::blink::PaymentHandlerStatus status) {
+  DCHECK(resolver);
+  if (rejectError(resolver, status))
+    return;
+  resolver->Resolve(keys);
+}
+
 void PaymentInstruments::onHasPaymentInstrument(
     ScriptPromiseResolver* resolver,
     payments::mojom::blink::PaymentHandlerStatus status) {