Add pref to enable/disable palette tray.

ash/common/system/status_area_widget.cc

 // Copyright (c) 2012 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/system/status_area_widget.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/system/overview/overview_button_tray.h"
 #include "ash/common/system/status_area_widget_delegate.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/system/web_notification/web_notification_tray.h"
 #include "ash/common/wm_lookup.h"
 #include "ash/common/wm_root_window_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
 #include "base/i18n/time_formatting.h"
 #include "ui/native_theme/native_theme_dark_aura.h"
 
 #if defined(OS_CHROMEOS)
 #include "ash/common/system/chromeos/ime_menu/ime_menu_tray.h"
 #include "ash/common/system/chromeos/palette/palette_tray.h"
+#include "ash/common/system/chromeos/palette/palette_utils.h"
 #include "ash/common/system/chromeos/session/logout_button_tray.h"
 #include "ash/common/system/chromeos/virtual_keyboard/virtual_keyboard_tray.h"
 #endif
 
 namespace ash {
 
 StatusAreaWidget::StatusAreaWidget(WmWindow* status_container,
                                    WmShelf* wm_shelf)
     : status_area_widget_delegate_(new StatusAreaWidgetDelegate),
       overview_button_tray_(nullptr),
@@ skipping 158 matching lines @@
 }
 
 void StatusAreaWidget::SchedulePaint() {
   status_area_widget_delegate_->SchedulePaint();
   web_notification_tray_->SchedulePaint();
   system_tray_->SchedulePaint();
 #if defined(OS_CHROMEOS)
   virtual_keyboard_tray_->SchedulePaint();
   logout_button_tray_->SchedulePaint();
   ime_menu_tray_->SchedulePaint();
-  palette_tray_->SchedulePaint();
+  if (palette_tray_)
+    palette_tray_->SchedulePaint();
 #endif
   overview_button_tray_->SchedulePaint();
 }
 
 const ui::NativeTheme* StatusAreaWidget::GetNativeTheme() const {
   return MaterialDesignController::IsShelfMaterial()
              ? ui::NativeThemeDarkAura::instance()
              : Widget::GetNativeTheme();
 }
 
 void StatusAreaWidget::OnNativeWidgetActivationChanged(bool active) {
   Widget::OnNativeWidgetActivationChanged(active);
   if (active)
     status_area_widget_delegate_->SetPaneFocusAndFocusDefault();
 }
 
 void StatusAreaWidget::UpdateShelfItemBackground(int alpha) {
   web_notification_tray_->UpdateShelfItemBackground(alpha);
   system_tray_->UpdateShelfItemBackground(alpha);
 #if defined(OS_CHROMEOS)
   virtual_keyboard_tray_->UpdateShelfItemBackground(alpha);
   logout_button_tray_->UpdateShelfItemBackground(alpha);
   ime_menu_tray_->UpdateShelfItemBackground(alpha);
-  palette_tray_->UpdateShelfItemBackground(alpha);
+  if (palette_tray_)
+    palette_tray_->UpdateShelfItemBackground(alpha);
 #endif
   overview_button_tray_->UpdateShelfItemBackground(alpha);
 }
 
 void StatusAreaWidget::AddSystemTray() {
   system_tray_ = new SystemTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(system_tray_);
 }
 
 void StatusAreaWidget::AddWebNotificationTray() {
   DCHECK(system_tray_);
   web_notification_tray_ = new WebNotificationTray(
       wm_shelf_, WmLookup::Get()->GetWindowForWidget(this), system_tray_);
   status_area_widget_delegate_->AddTray(web_notification_tray_);
 }
 
 #if defined(OS_CHROMEOS)
 void StatusAreaWidget::AddLogoutButtonTray() {
   logout_button_tray_ = new LogoutButtonTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(logout_button_tray_);
 }
 
 void StatusAreaWidget::AddPaletteTray() {
-  palette_tray_ = new PaletteTray(wm_shelf_);
-  status_area_widget_delegate_->AddTray(palette_tray_);
+  if (IsPaletteFeatureEnabled()) {
+    palette_tray_ = new PaletteTray(wm_shelf_);
+    status_area_widget_delegate_->AddTray(palette_tray_);
+  }
 }
 
 void StatusAreaWidget::AddVirtualKeyboardTray() {
   virtual_keyboard_tray_ = new VirtualKeyboardTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(virtual_keyboard_tray_);
 }
 
 void StatusAreaWidget::AddImeMenuTray() {
   ime_menu_tray_ = new ImeMenuTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(ime_menu_tray_);
@@ skipping 16 matching lines @@
   return false;
 }
 #endif
 
 void StatusAreaWidget::AddOverviewButtonTray() {
   overview_button_tray_ = new OverviewButtonTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(overview_button_tray_);
 }
 
 }  // namespace ash