[Payments] Handle clicking back on the CVC unmask dialog

chrome/browser/ui/views/payments/cvc_unmask_view_controller.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 "chrome/browser/ui/views/payments/cvc_unmask_view_controller.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/autofill/risk_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
@@ skipping 91 matching lines @@
 
 void CvcUnmaskViewController::ShowUnmaskPrompt(
     const autofill::CreditCard& card,
     autofill::AutofillClient::UnmaskCardReason reason,
     base::WeakPtr<autofill::CardUnmaskDelegate> delegate) {
   unmask_delegate_ = delegate;
 }
 
 void CvcUnmaskViewController::OnUnmaskVerificationResult(
     autofill::AutofillClient::PaymentsRpcResult result) {
-  // TODO(anthonyvd): Show result.
+  // TODO(crbug.com/716020): Handle FullCardRequest errors with more
+  // granularity and display an error in the UI.
 }
 
 base::string16 CvcUnmaskViewController::GetSheetTitle() {
   return l10n_util::GetStringFUTF16(IDS_AUTOFILL_CARD_UNMASK_PROMPT_TITLE,
                                     credit_card_.TypeAndLastFourDigits());
 }
 
 void CvcUnmaskViewController::FillContentView(views::View* content_view) {
   std::unique_ptr<views::GridLayout> layout =
       base::MakeUnique<views::GridLayout>(content_view);
@@ skipping 53 matching lines @@
   button->set_tag(static_cast<int>(Tags::CONFIRM_TAG));
   return button;
 }
 
 void CvcUnmaskViewController::ButtonPressed(views::Button* sender,
                                             const ui::Event& event) {
   switch (sender->tag()) {
     case static_cast<int>(Tags::CONFIRM_TAG):
       CvcConfirmed();
       break;
+    case static_cast<int>(PaymentRequestCommonTags::BACK_BUTTON_TAG):
+      unmask_delegate_->OnUnmaskPromptClosed();
+      dialog()->GoBack();
+      break;
     default:
       PaymentRequestSheetController::ButtonPressed(sender, event);
   }
 }
 
 void CvcUnmaskViewController::CvcConfirmed() {
   const base::string16& cvc = cvc_field_->text();
   if (unmask_delegate_) {
     autofill::CardUnmaskDelegate::UnmaskResponse response;
     response.cvc = cvc;
     unmask_delegate_->OnUnmaskResponse(response);
   }
 
   dialog()->ShowProcessingSpinner();
 }
 
 }  // namespace payments