[Payment Request] Remove Cancel button in the Order Summary sheet.

Bug: 866736
Change-Id: I2ead391e93eb64a4622ad94d75d34755e831c50f
Reviewed-on: https://chromium-review.googlesource.com/1147756Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Commit-Queue: Mathieu Perreault <mathp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577598}

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

@@ -151,6 +151,10 @@ OrderSummaryViewController::CreatePrimaryButton() {
   return button;
 }
 
+bool OrderSummaryViewController::ShouldShowSecondaryButton() {
+  return false;
+}
+
 base::string16 OrderSummaryViewController::GetSheetTitle() {
   return l10n_util::GetStringUTF16(IDS_PAYMENTS_ORDER_SUMMARY_LABEL);
 }

chrome/browser/ui/views/payments/order_summary_view_controller.h

@@ -40,6 +40,7 @@ class OrderSummaryViewController : public PaymentRequestSheetController,
  private:
   // PaymentRequestSheetController:
   std::unique_ptr<views::Button> CreatePrimaryButton() override;
+  bool ShouldShowSecondaryButton() override;
   base::string16 GetSheetTitle() override;
   void FillContentView(views::View* content_view) override;
   void UpdatePayButtonState(bool enabled);