MacViews: Implement Full Keyboard Access.

ash/system/user/button_from_view.cc

 // Copyright 2014 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/system/user/button_from_view.h"
 
 #include "ash/ash_constants.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_utils.h"
 #include "base/strings/string_util.h"
@@ skipping 25 matching lines @@
       button_hovered_(false),
       show_border_(false),
       tab_frame_inset_(tab_frame_inset) {
   set_notify_enter_exit_on_child(true);
   SetLayoutManager(
       new views::BoxLayout(views::BoxLayout::kHorizontal, 1, 1, 0));
   AddChildView(content_);
   ShowActive();
   // Only make it focusable when we are active/interested in clicks.
   if (listener)
-    SetFocusBehavior(FocusBehavior::ALWAYS);
+    Button::ConfigureDefaultFocus(this);
 }
 
 ButtonFromView::~ButtonFromView() {}
 
 void ButtonFromView::ForceBorderVisible(bool show) {
   show_border_ = show;
   ShowActive();
 }
 
 void ButtonFromView::OnMouseEntered(const ui::MouseEvent& event) {
@@ skipping 45 matching lines @@
         button_hovered_ ? kHoverBackgroundColor : kBackgroundColor;
     content_->set_background(
         views::Background::CreateSolidBackground(background_color));
     set_background(views::Background::CreateSolidBackground(background_color));
   }
   SchedulePaint();
 }
 
 }  // namespace tray
 }  // namespace ash