[WebPayments] Making all fields and buttons focusable

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

 // 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.
 
 #include "chrome/browser/ui/views/payments/validating_combobox.h"
 
 #include <utility>
 
 #include "ui/base/models/combobox_model.h"
 
 namespace payments {
 
 ValidatingCombobox::ValidatingCombobox(
     std::unique_ptr<ui::ComboboxModel> model,
     std::unique_ptr<ValidationDelegate> delegate)
     : Combobox(std::move(model)), delegate_(std::move(delegate)) {
   // No need to remove observer on owned model.
   this->model()->AddObserver(this);
+  SetFocusBehavior(FocusBehavior::ALWAYS);
 }
 
 ValidatingCombobox::~ValidatingCombobox() {}
 
 void ValidatingCombobox::OnBlur() {
   Combobox::OnBlur();
 
   // Validations will occur when the content changes. Do not validate if the
   // view is being removed.
   if (!being_removed_) {
@@ skipping 20 matching lines @@
 bool ValidatingCombobox::IsValid() {
   return delegate_->IsValidCombobox(this);
 }
 
 void ValidatingCombobox::Validate() {
   // ComboboxValueChanged may have side-effects, such as displaying errors.
   SetInvalid(!delegate_->ComboboxValueChanged(this));
 }
 
 }  // namespace payments