Give up focus if the focused view becomes unfocusable

ash/system/tray/tray_popup_header_button.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/system/tray/tray_popup_header_button.h"
 
 #include "ash/ash_constants.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
@@ skipping 18 matching lines @@
       bundle.GetImageNamed(enabled_resource_id).ToImageSkia());
   SetToggledImage(views::Button::STATE_NORMAL,
       bundle.GetImageNamed(disabled_resource_id).ToImageSkia());
   SetImage(views::Button::STATE_HOVERED,
       bundle.GetImageNamed(enabled_resource_id_hover).ToImageSkia());
   SetToggledImage(views::Button::STATE_HOVERED,
       bundle.GetImageNamed(disabled_resource_id_hover).ToImageSkia());
   SetImageAlignment(views::ImageButton::ALIGN_CENTER,
                     views::ImageButton::ALIGN_MIDDLE);
   SetAccessibleName(bundle.GetLocalizedString(accessible_name_id));
-  set_focusable(true);
+  SetFocusable(true);
   set_request_focus_on_press(false);
 
   SetFocusPainter(views::Painter::CreateSolidFocusPainter(
                       kFocusBorderColor,
                       gfx::Insets(1, 2, 2, 3)));
 }
 
 TrayPopupHeaderButton::~TrayPopupHeaderButton() {}
 
 const char* TrayPopupHeaderButton::GetClassName() const {
@@ skipping 11 matching lines @@
   canvas->FillRect(gfx::Rect(0, padding, 1, height() - padding * 2),
       ash::kBorderDarkColor);
 }
 
 void TrayPopupHeaderButton::StateChanged() {
   SchedulePaint();
 }
 
 }  // namespace internal
 }  // namespace ash