Fix stylus tools palette.

ash/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/system/status_area_widget.h"
 
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
 #include "ash/shelf/wm_shelf.h"
 #include "ash/shell.h"
@@ skipping 191 matching lines @@
       wm_shelf_, WmWindow::Get(this->GetNativeWindow()), system_tray_);
   status_area_widget_delegate_->AddTray(web_notification_tray_);
 }
 
 void StatusAreaWidget::AddLogoutButtonTray() {
   logout_button_tray_ = new LogoutButtonTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(logout_button_tray_);
 }
 
 void StatusAreaWidget::AddPaletteTray() {
   const display::Display& display =

[jdufault, 2017/04/19 22:58:38]

Instead of checking in the if below just short-circuit the function.

  if (!palette_utils::HasStylusInput())
    return;

[wutao, 2017/04/20 16:17:51]

Done.

       WmWindow::Get(this->GetNativeWindow())->GetDisplayNearestWindow();
 
   // Create the palette only on the internal display, where the stylus is
   // available. We also create a palette on every display if requested from the
   // command line.
-  if (display.IsInternal() || palette_utils::IsPaletteEnabledOnEveryDisplay()) {
+  if (palette_utils::HasStylusInput() &&
+      (display.IsInternal() ||
+       palette_utils::IsPaletteEnabledOnEveryDisplay())) {
     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_);
 }
 
 void StatusAreaWidget::AddOverviewButtonTray() {
   overview_button_tray_ = new OverviewButtonTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(overview_button_tray_);
 }
 
 }  // namespace ash