[Payments] Add error messages to credit card editor.

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

Index: chrome/browser/ui/views/payments/payment_request_interactive_uitest_base.cc
diff --git a/chrome/browser/ui/views/payments/payment_request_interactive_uitest_base.cc b/chrome/browser/ui/views/payments/payment_request_interactive_uitest_base.cc
index 02f114e78f49f0b4a2e6a24c454821a7b36b5385..991adf435057ff391cf3a807b5bf3a3354b834c6 100644
--- a/chrome/browser/ui/views/payments/payment_request_interactive_uitest_base.cc
+++ b/chrome/browser/ui/views/payments/payment_request_interactive_uitest_base.cc
@@ -30,6 +30,7 @@
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/test/ui_controls.h"
 #include "ui/gfx/animation/test_animation_delegate.h"
+#include "ui/views/controls/label.h"
 #include "ui/views/controls/styled_label.h"
 
 namespace payments {
@@ -243,6 +244,14 @@ const base::string16& PaymentRequestInteractiveTestBase::GetStyledLabelText(
   return static_cast<views::StyledLabel*>(view)->text();
 }
 
+const base::string16& PaymentRequestInteractiveTestBase::GetErrorLabelForType(
+    autofill::ServerFieldType type) {
+  views::View* view = dialog_view()->GetViewByID(
+      static_cast<int>(DialogViewID::ERROR_LABEL_OFFSET) + type);
+  DCHECK(view);
+  return static_cast<views::Label*>(view)->text();
+}
+
 PaymentRequestInteractiveTestBase::DialogEventObserver::DialogEventObserver(
     PaymentRequestInteractiveTestBase::DialogEvent event)
     : event_(event), seen_(false) {}