Fix stylus tools palette.

ash/system/palette/palette_utils.h

 // Copyright 2016 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.
 
 #ifndef ASH_SYSTEM_PALETTE_PALETTE_UTILS_H_
 #define ASH_SYSTEM_PALETTE_PALETTE_UTILS_H_
 
 #include "ash/ash_export.h"
 
 namespace gfx {
 class Point;
 }
 
 namespace ash {
 namespace palette_utils {
 
 // Returns true if there is a stylus input device on the internal display. This
 // will return false even if there is a stylus input device until hardware
 // probing is complete (see ui::InputDeviceEventObserver).
 ASH_EXPORT bool HasStylusInput();
 
 // Returns true if the palette should be shown on every display.
 ASH_EXPORT bool IsPaletteEnabledOnEveryDisplay();
 
+// Returns true if the palette should be shown to the user. This happens when:
+// there is a stylus input, there is an internal display, and the user has not
+// disabled it in settings. This can be overridden by passing switches.
+ASH_EXPORT bool ShouldShowPalette();
+
 // Returns true if either the palette icon or the palette widget contain the
 // given point (in screen space).
 ASH_EXPORT bool PaletteContainsPointInScreen(const gfx::Point& point);
 
 }  // namespace palette_utils
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_PALETTE_PALETTE_UTILS_H_