[Payments] Add error messages to credit card editor.

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

Index: chrome/browser/ui/views/payments/credit_card_editor_view_controller.h
diff --git a/chrome/browser/ui/views/payments/credit_card_editor_view_controller.h b/chrome/browser/ui/views/payments/credit_card_editor_view_controller.h
index 4ea2ef71990b2bf50ccd40f986b9e5916aa95b8e..c13e8f7a6000940311b250c3f85c510cf4794744 100644
--- a/chrome/browser/ui/views/payments/credit_card_editor_view_controller.h
+++ b/chrome/browser/ui/views/payments/credit_card_editor_view_controller.h
@@ -35,7 +35,8 @@ class CreditCardEditorViewController : public EditorViewController {
  private:
   class CreditCardValidationDelegate : public ValidationDelegate {
    public:
-    explicit CreditCardValidationDelegate(const EditorField& field);
+    CreditCardValidationDelegate(const EditorField& field,
+                                 EditorViewController* controller);
     ~CreditCardValidationDelegate() override;
 
     // ValidationDelegate:
@@ -47,6 +48,8 @@ class CreditCardEditorViewController : public EditorViewController {
     bool ValidateValue(const base::string16& value);
 
     EditorField field_;
+    // Outlives this class.
+    EditorViewController* controller_;
 
     DISALLOW_COPY_AND_ASSIGN(CreditCardValidationDelegate);
   };