Focus first invalid field of payment request editor

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

 // 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_PAYMENTS_VALIDATING_TEXTFIELD_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_VALIDATING_TEXTFIELD_H_
 
+#include <memory>
+
 #include "base/macros.h"
 #include "chrome/browser/ui/views/payments/validation_delegate.h"
 #include "ui/views/controls/textfield/textfield.h"
 
 namespace payments {
 
 class ValidatingTextfield : public views::Textfield {
  public:
   explicit ValidatingTextfield(std::unique_ptr<ValidationDelegate> delegate);
   ~ValidatingTextfield() override;
 
   // Textfield:
   // The first validation will happen on blur.
   void OnBlur() override;
   // Used to keep track of our own destruction.
   void ViewHierarchyChanged(
       const ViewHierarchyChangedDetails& details) override;
 
   // Called when the textfield contents is changed. May do validation.
   void OnContentsChanged();
 
+  // Identifies whether the current content if valid or not.
+  bool IsValid();
+
  private:
   // Will call to the ValidationDelegate to validate the contents of the
   // textfield.
   void Validate();
 
   std::unique_ptr<ValidationDelegate> delegate_;
   bool was_blurred_ = false;
   bool being_removed_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(ValidatingTextfield);
 };
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_VALIDATING_TEXTFIELD_H_