Support allowpaymentrequest with out-of-process iframes

BUG=669585

Review-Url: https://codereview.chromium.org/2545693002
Cr-Commit-Position: refs/heads/master@{#438724}
diff --git a/chrome/browser/payments/payment_request_impl.h b/chrome/browser/payments/payment_request_impl.h
index 39ee68f..fe3b6e7 100644
--- a/chrome/browser/payments/payment_request_impl.h
+++ b/chrome/browser/payments/payment_request_impl.h
@@ -26,7 +26,7 @@
             std::vector<payments::mojom::PaymentMethodDataPtr> methodData,
             payments::mojom::PaymentDetailsPtr details,
             payments::mojom::PaymentOptionsPtr options) override;
-  void Show() override {}
+  void Show() override;
   void UpdateWith(payments::mojom::PaymentDetailsPtr details) override {}
   void Abort() override {}
   void Complete(payments::mojom::PaymentComplete result) override {}