PaymentRequest.canMakePayment() query quota on desktop.

components/payments/core/can_make_payment_query.h

Index: components/payments/core/can_make_payment_query.h
diff --git a/components/payments/core/can_make_payment_query.h b/components/payments/core/can_make_payment_query.h
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+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_PAYMENTS_CORE_CAN_MAKE_PAYMENT_QUERY_H_
+#define COMPONENTS_PAYMENTS_CORE_CAN_MAKE_PAYMENT_QUERY_H_
+
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+
+#include "base/macros.h"
+#include "base/timer/timer.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "url/gurl.h"
+
+namespace payments {
+
+// Keeps track of canMakePayment() queries per browser context.
+class CanMakePaymentQuery : public KeyedService {
+ public:
+  CanMakePaymentQuery();
+  ~CanMakePaymentQuery() override;
+
+  // Returns whether |frame_origin| can call canMakePayment() with |query|,
+  // which is a mapping of payment method names to the corresponding
+  // JSON-stringified payment method data. Remembers the frame-to-query mapping
+  // for 30 minutes to enforce the quota.
+  bool CanQuery(const GURL& frame_origin,
+                const std::map<std::string, std::set<std::string>>& query);
+
+ private:
+  void ExpireQuotaForFrameOrigin(const GURL& frame_origin);
+
+  // A mapping of frame origin to the timer that, when fired, allows the frame
+  // to invoke canMakePayment() with a different query.
+  std::map<GURL, std::unique_ptr<base::OneShotTimer>> timers_;
+
+  // A mapping of frame origin to its last query. Each query is a mapping of
+  // payment method names to the corresponding JSON-stringified payment method
+  // data.
+  std::map<GURL, std::map<std::string, std::set<std::string>>> queries_;
+
+  DISALLOW_COPY_AND_ASSIGN(CanMakePaymentQuery);
+};
+
+}  // namespace payments
+
+#endif  // COMPONENTS_PAYMENTS_CORE_CAN_MAKE_PAYMENT_QUERY_H_