[Payments] Handle clicking back on the CVC unmask dialog

chrome/browser/ui/views/payments/cvc_unmask_view_controller_browsertest.cc

 // 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.
 
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/ui/views/payments/payment_request_browsertest_base.h"
 #include "components/autofill/core/browser/autofill_test_utils.h"
 
 namespace payments {
 
-class CvcUnmaskViewControllerTest : public PaymentRequestBrowserTestBase {
+class PaymentRequestCvcUnmaskViewControllerTest
+    : public PaymentRequestBrowserTestBase {
  protected:
-  CvcUnmaskViewControllerTest()
+  PaymentRequestCvcUnmaskViewControllerTest()
       : PaymentRequestBrowserTestBase(
             "/payment_request_no_shipping_test.html") {}
 
  private:
-  DISALLOW_COPY_AND_ASSIGN(CvcUnmaskViewControllerTest);
+  DISALLOW_COPY_AND_ASSIGN(PaymentRequestCvcUnmaskViewControllerTest);
 };
 
-IN_PROC_BROWSER_TEST_F(CvcUnmaskViewControllerTest, CvcSentToResponse) {
+IN_PROC_BROWSER_TEST_F(PaymentRequestCvcUnmaskViewControllerTest,
+                       CvcSentToResponse) {
   AddCreditCard(autofill::test::GetCreditCard());  // Visa.
 
   InvokePaymentRequestUI();
   ResetEventObserver(DialogEvent::DIALOG_CLOSED);
   PayWithCreditCardAndWait(base::ASCIIToUTF16("012"));
 
   ExpectBodyContains({"\"cardSecurityCode\": \"012\""});
 }
 
+// Test that going in the CVC editor, backing out and opening it again to pay
+// does not crash.
+IN_PROC_BROWSER_TEST_F(PaymentRequestCvcUnmaskViewControllerTest,
+                       OpenGoBackOpenPay) {
+  AddCreditCard(autofill::test::GetCreditCard());  // Visa.
+
+  InvokePaymentRequestUI();
+  OpenCVCPromptWithCVC(base::ASCIIToUTF16("012"));
+
+  // Go back before confirming the CVC.
+  ClickOnBackArrow();
+
+  // Now pay for real.
+  PayWithCreditCardAndWait(base::ASCIIToUTF16("012"));
+  ExpectBodyContains({"\"cardSecurityCode\": \"012\""});
+}
+
 }  // namespace payments