[PlayBilling] Total optional on only app-store billing requested

Context:
Total is a field in the "new PaymentRequest()" API. It specifies the
amount and currency of the payment request. However, when the merchant
requests for the app-store billing (e.g., Google Play Store billing -
by specifying "https://play.google.com/billing" as the method), the
total field becomes unnecessary. This is because app-stores takes
the total from elsewhere.

Before:
The total field is mandatory for PaymentRequest.

After:
The total field is optional if only app-store methods are requested.
When total field is optional and left out, Chrome would add a total of
amount 0, currency "ZZZ" and label "AppStoreBillingTotalPlaceHolder".

Change:
* Added a RuntimeEnabledFeature: PaymentRequestTotalOptional
* Added an about flag: payment-request-optional-total
* change the optionality of the total field and details field of
PaymentRequest API.

Related Doc:
* Chrome Status: https://www.chromestatus.com/feature/5226111782879232
* Intent to Prototype: https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/TJVn0Ps9ugA/3unr2Vo8AgAJ
* W3C explainer: w3c/payment-request#912

Bug: 1066531

Change-Id: Id5ad87b9fc452fd41a1ebef066d981737545a235
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2150974
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Liquan (Max) Gu <maxlg@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#769914}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: f8f56a44e023414f59c86350cea68ae4cf8009aa

blink/public/platform/web_runtime_features.h

@@ -136,6 +136,7 @@ class WebRuntimeFeatures {
   BLINK_PLATFORM_EXPORT static void EnablePagePopup(bool);
   BLINK_PLATFORM_EXPORT static void EnablePaymentApp(bool);
   BLINK_PLATFORM_EXPORT static void EnablePaymentHandlerMinimalUI(bool);
+  BLINK_PLATFORM_EXPORT static void EnablePaymentRequestOptionalTotal(bool);
   BLINK_PLATFORM_EXPORT static void EnablePaymentRequest(bool);
   BLINK_PLATFORM_EXPORT static void EnablePercentBasedScrolling(bool);
   BLINK_PLATFORM_EXPORT static void EnablePerformanceManagerInstrumentation(

blink/renderer/modules/BUILD.gn

@@ -367,6 +367,7 @@ jumbo_source_set("unit_tests") {
     "payments/payment_address_test.cc",
     "payments/payment_event_data_conversion_test.cc",
     "payments/payment_request_details_test.cc",
+    "payments/payment_request_optional_total_test.cc",
     "payments/payment_request_test.cc",
     "payments/payment_request_update_event_test.cc",
     "payments/payment_response_test.cc",

blink/renderer/modules/payments/payment_details_init.idl

@@ -2,9 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// https://w3c.github.io/browser-payment-api/#paymentdetailsinit-dictionary
+// https://w3c.github.io/payment-request/#paymentdetailsinit-dictionary
 
 dictionary PaymentDetailsInit : PaymentDetailsBase {
     DOMString id;
-    required PaymentItem total;
+    PaymentItem total;
 };

blink/renderer/modules/payments/payment_request.cc

@@ -8,6 +8,7 @@
 
 #include <utility>
 
+#include "base/bind.h"
 #include "base/location.h"
 #include "base/stl_util.h"
 #include "build/build_config.h"
@@ -93,6 +94,9 @@ using ::payments::mojom::blink::PaymentValidationErrorsPtr;
 const char kHasEnrolledInstrumentDebugName[] = "hasEnrolledInstrument";
 const char kGooglePayMethod[] = "https://google.com/pay";
 const char kAndroidPayMethod[] = "https://android.com/pay";
+const char kGooglePlayBillingMethod[] = "https://play.google.com/billing";
+const char kUnknownCurrency[] = "ZZZ";
+const char kAppStoreBillingLabelPlaceHolder[] = "AppStoreBillingPlaceHolder";
 
 }  // namespace
 
@@ -266,6 +270,18 @@ void ValidateShippingOptionOrPaymentItem(const T* item,
   }
 }
 
+bool RequestingOnlyAppStoreBillingMethods(
+    const Vector<payments::mojom::blink::PaymentMethodDataPtr>& method_data) {
+  DCHECK(!method_data.IsEmpty());
+  static const WTF::HashSet<String> app_store_billing_methods = {
+      kGooglePlayBillingMethod};
+  for (const auto& method : method_data) {
+    if (!app_store_billing_methods.Contains(method->supported_method))
+      return false;
+  }
+  return true;
+}
+
 void ValidateAndConvertDisplayItems(
     const HeapVector<Member<PaymentItem>>& input,
     const String& item_names,
@@ -504,17 +520,50 @@ void ValidateAndConvertPaymentDetailsBase(const PaymentDetailsBase* input,
   }
 }
 
+PaymentItemPtr CreateTotalPlaceHolderForAppStoreBilling(
+    ExecutionContext& execution_context) {
+  PaymentItemPtr total = payments::mojom::blink::PaymentItem::New();
+  total->label = kAppStoreBillingLabelPlaceHolder;
+  total->amount = payments::mojom::blink::PaymentCurrencyAmount::New();
+  total->amount->currency = kUnknownCurrency;
+  total->amount->value = "0";
+
+  return total;
+}
+
 void ValidateAndConvertPaymentDetailsInit(const PaymentDetailsInit* input,
                                           const PaymentOptions* options,
                                           PaymentDetailsPtr& output,
                                           String& shipping_option_output,
+                                          bool ignore_total,
                                           ExecutionContext& execution_context,
                                           ExceptionState& exception_state) {
-  DCHECK(input->hasTotal());
-  ValidateAndConvertTotal(input->total(), "total", output->total,
-                          execution_context, exception_state);
-  if (exception_state.HadException())
-    return;
+  if (ignore_total) {
+    output->total = CreateTotalPlaceHolderForAppStoreBilling(execution_context);
+    if (input->hasTotal()) {
+      execution_context.AddConsoleMessage(MakeGarbageCollected<ConsoleMessage>(
+          mojom::blink::ConsoleMessageSource::kJavaScript,
+          mojom::blink::ConsoleMessageLevel::kWarning,
+          "Specified total is ignored for in-app purchases with app stores. "
+          "User will be shown the total derived from the product identifier."));
+    }
+  } else {
+    // Whether details (i.e., input) being omitted, null, defined or {} is
+    // indistinguishable, so we check all of its attributes to decide whether it
+    // has been provided.
+    if (!input->hasTotal() && !input->hasId()) {
+      exception_state.ThrowTypeError("required member details is undefined.");
+      return;
+    }
+    if (!input->hasTotal()) {
+      exception_state.ThrowTypeError("required member total is undefined.");
+      return;
+    }
+    ValidateAndConvertTotal(input->total(), "total", output->total,
+                            execution_context, exception_state);
+    if (exception_state.HadException())
+      return;
+  }
 
   ValidateAndConvertPaymentDetailsBase(input, options, output,
                                        shipping_option_output,
@@ -525,19 +574,26 @@ void ValidateAndConvertPaymentDetailsUpdate(const PaymentDetailsUpdate* input,
                                             const PaymentOptions* options,
                                             PaymentDetailsPtr& output,
                                             String& shipping_option_output,
+                                            bool ignore_total,
                                             ExecutionContext& execution_context,
                                             ExceptionState& exception_state) {
   ValidateAndConvertPaymentDetailsBase(input, options, output,
                                        shipping_option_output,
                                        execution_context, exception_state);
   if (exception_state.HadException())
     return;
-
   if (input->hasTotal()) {
-    ValidateAndConvertTotal(input->total(), "total", output->total,
-                            execution_context, exception_state);
-    if (exception_state.HadException())
-      return;
+    DCHECK(!RuntimeEnabledFeatures::PaymentRequestOptionalTotalEnabled() ||
+           !ignore_total);
+    if (ignore_total) {
+      output->total =
+          CreateTotalPlaceHolderForAppStoreBilling(execution_context);
+    } else {
+      ValidateAndConvertTotal(input->total(), "total", output->total,
+                              execution_context, exception_state);
+      if (exception_state.HadException())
+        return;
+    }
   }
 
   if (input->hasError()) {
@@ -665,9 +721,9 @@ PaymentRequest* PaymentRequest::Create(
     const HeapVector<Member<PaymentMethodData>>& method_data,
     const PaymentDetailsInit* details,
     ExceptionState& exception_state) {
-  return MakeGarbageCollected<PaymentRequest>(execution_context, method_data,
-                                              details, PaymentOptions::Create(),
-                                              exception_state);
+  return MakeGarbageCollected<PaymentRequest>(
+      execution_context, method_data, details, PaymentOptions::Create(),
+      mojo::NullRemote(), exception_state);
 }
 
 PaymentRequest* PaymentRequest::Create(
@@ -677,7 +733,8 @@ PaymentRequest* PaymentRequest::Create(
     const PaymentOptions* options,
     ExceptionState& exception_state) {
   return MakeGarbageCollected<PaymentRequest>(
-      execution_context, method_data, details, options, exception_state);
+      execution_context, method_data, details, options, mojo::NullRemote(),
+      exception_state);
 }
 
 PaymentRequest::~PaymentRequest() = default;
@@ -982,7 +1039,7 @@ void PaymentRequest::OnUpdatePaymentDetails(
   PaymentDetailsPtr validated_details =
       payments::mojom::blink::PaymentDetails::New();
   ValidateAndConvertPaymentDetailsUpdate(
-      details, options_, validated_details, shipping_option_,
+      details, options_, validated_details, shipping_option_, ignore_total_,
       *GetExecutionContext(), exception_state);
   if (exception_state.HadException()) {
     resolver->Reject(exception_state.GetException());
@@ -1067,6 +1124,8 @@ PaymentRequest::PaymentRequest(
     const HeapVector<Member<PaymentMethodData>>& method_data,
     const PaymentDetailsInit* details,
     const PaymentOptions* options,
+    mojo::PendingRemote<payments::mojom::blink::PaymentRequest>
+        mock_payment_provider,
     ExceptionState& exception_state)
     : ExecutionContextLifecycleObserver(execution_context),
       options_(options),
@@ -1081,8 +1140,8 @@ PaymentRequest::PaymentRequest(
           this,
           &PaymentRequest::OnUpdatePaymentDetailsTimeout),
       is_waiting_for_show_promise_to_resolve_(false) {
+  DCHECK(details);
   DCHECK(GetExecutionContext()->IsSecureContext());
-
   if (!AllowedToUsePaymentRequest(execution_context)) {
     exception_state.ThrowSecurityError(
         "Must be in a top-level browsing context or an iframe needs to specify "
@@ -1114,9 +1173,12 @@ PaymentRequest::PaymentRequest(
   if (exception_state.HadException())
     return;
 
+  ignore_total_ =
+      RuntimeEnabledFeatures::PaymentRequestOptionalTotalEnabled() &&
+      RequestingOnlyAppStoreBillingMethods(validated_method_data);
   ValidateAndConvertPaymentDetailsInit(details, options_, validated_details,
-                                       shipping_option_, *GetExecutionContext(),
-                                       exception_state);
+                                       shipping_option_, ignore_total_,
+                                       *GetExecutionContext(), exception_state);
   if (exception_state.HadException())
     return;
 
@@ -1143,8 +1205,14 @@ PaymentRequest::PaymentRequest(
   scoped_refptr<base::SingleThreadTaskRunner> task_runner =
       execution_context->GetTaskRunner(TaskType::kUserInteraction);
 
-  GetFrame()->GetBrowserInterfaceBroker().GetInterface(
-      payment_provider_.BindNewPipeAndPassReceiver(task_runner));
+  if (mock_payment_provider) {
+    payment_provider_.Bind(
+        std::move(mock_payment_provider),
+        execution_context->GetTaskRunner(TaskType::kMiscPlatformAPI));
+  } else {
+    GetFrame()->GetBrowserInterfaceBroker().GetInterface(
+        payment_provider_.BindNewPipeAndPassReceiver(task_runner));
+  }
   payment_provider_.set_disconnect_handler(
       WTF::Bind(&PaymentRequest::OnConnectionError, WrapWeakPersistent(this)));
 

blink/renderer/modules/payments/payment_request.h

@@ -65,6 +65,8 @@ class MODULES_EXPORT PaymentRequest final
                  const HeapVector<Member<PaymentMethodData>>&,
                  const PaymentDetailsInit*,
                  const PaymentOptions*,
+                 mojo::PendingRemote<payments::mojom::blink::PaymentRequest>
+                     mock_payment_provider,
                  ExceptionState&);
   ~PaymentRequest() override;
 
@@ -179,6 +181,7 @@ class MODULES_EXPORT PaymentRequest final
   TaskRunnerTimer<PaymentRequest> complete_timer_;
   TaskRunnerTimer<PaymentRequest> update_payment_details_timer_;
   bool is_waiting_for_show_promise_to_resolve_;
+  bool ignore_total_;
 
   DISALLOW_COPY_AND_ASSIGN(PaymentRequest);
 };

blink/renderer/modules/payments/payment_request.idl

@@ -11,7 +11,7 @@
     Exposed=Window,
     ActiveScriptWrappable
 ] interface PaymentRequest : EventTarget {
-    [CallWith=ExecutionContext, RaisesException] constructor(sequence<PaymentMethodData> methodData, PaymentDetailsInit details, optional PaymentOptions options = {});
+    [CallWith=ExecutionContext, RaisesException] constructor(sequence<PaymentMethodData> methodData, optional PaymentDetailsInit details = {}, optional PaymentOptions options = {});
     [CallWith=ScriptState, RaisesException, NewObject] Promise<PaymentResponse> show(optional Promise<PaymentDetailsUpdate> detailsPromise);
     [CallWith=ScriptState, RaisesException, NewObject] Promise<void> abort();
     [CallWith=ScriptState, RaisesException, HighEntropy, Measure, NewObject] Promise<boolean> canMakePayment();