Add a regression test for the CardUnmaskPrompt.

chrome/browser/ui/autofill/card_unmask_prompt_controller_impl.cc

Index: chrome/browser/ui/autofill/card_unmask_prompt_controller_impl.cc
diff --git a/chrome/browser/ui/autofill/card_unmask_prompt_controller_impl.cc b/chrome/browser/ui/autofill/card_unmask_prompt_controller_impl.cc
index 19fdcaf998626985b92f105c24423416a77c9d41..7dfc75eae59dcabebe555b6f3830db84c0fe73af 100644
--- a/chrome/browser/ui/autofill/card_unmask_prompt_controller_impl.cc
+++ b/chrome/browser/ui/autofill/card_unmask_prompt_controller_impl.cc
@@ -36,10 +36,6 @@ CardUnmaskPromptControllerImpl::~CardUnmaskPromptControllerImpl() {
     card_unmask_view_->ControllerGone();
 }
 
-CardUnmaskPromptView* CardUnmaskPromptControllerImpl::CreateAndShowView() {
-  return CardUnmaskPromptView::CreateAndShow(this);
-}
-
 void CardUnmaskPromptControllerImpl::ShowPrompt(
     const CreditCard& card,
     base::WeakPtr<CardUnmaskDelegate> delegate) {
@@ -261,6 +257,15 @@ bool CardUnmaskPromptControllerImpl::InputExpirationIsValid(
   return month_value >= now.month;
 }
 
+base::TimeDelta CardUnmaskPromptControllerImpl::GetSuccessMessageDuration()
+    const {
+  return base::TimeDelta::FromMilliseconds(500);
+}
+
+CardUnmaskPromptView* CardUnmaskPromptControllerImpl::CreateAndShowView() {
+  return CardUnmaskPromptView::CreateAndShow(this);
+}
+
 void CardUnmaskPromptControllerImpl::LoadRiskFingerprint() {
   LoadRiskData(
       0, web_contents_,