Reduce views::Border creation verbosity by promoting factory functions

ash/common/wm/overview/window_selector_item.cc

 // Copyright 2013 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 "ash/common/wm/overview/window_selector_item.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "ash/common/material_design/material_design_controller.h"
@@ skipping 614 matching lines @@
   params_label.accept_events = true;
   root_window_->GetRootWindowController()
       ->ConfigureWidgetInitParamsForContainer(
           window_label_.get(),
           transform_window_.window()->GetParent()->GetShellWindowId(),
           &params_label);
   window_label_.reset(new views::Widget);
   window_label_->set_focus_on_creation(false);
   window_label_->Init(params_label);
   window_label_button_view_ = new OverviewLabelButton(this, title);
-  window_label_button_view_->SetBorder(views::Border::NullBorder());
+  window_label_button_view_->SetBorder(views::NullBorder());
   window_label_button_view_->SetEnabledTextColors(kLabelColor);
   window_label_button_view_->set_animate_on_state_change(false);
   WmWindow* label_window =
       WmLookup::Get()->GetWindowForWidget(window_label_.get());
   if (transform_window_.GetTopInset()) {
     // For windows with headers the overview header fades in above the
     // original window header.
     label_window->GetParent()->StackChildAbove(label_window,
                                                transform_window_.window());
   } else {
@@ skipping 135 matching lines @@
   window_selector_->delegate()->AddDelayedAnimationObserver(
       std::move(observer));
   widget_ptr->SetOpacity(0.f);
 }
 
 gfx::SlideAnimation* WindowSelectorItem::GetBackgroundViewAnimation() {
   return background_view_ ? background_view_->animation() : nullptr;
 }
 
 }  // namespace ash