cros: Use runtime stylus detection for ash palette.

ash/common/system/chromeos/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_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_UTILS_H_
 #define ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_UTILS_H_
 
 #include "ash/ash_export.h"
 
 namespace gfx {
 class Point;
 }
 
 namespace ash {
+namespace palette_utils {
 
-// Returns true if the palette feature is enabled. The palette itself may have
-// been disabled by the user.
-ASH_EXPORT bool IsPaletteFeatureEnabled();
+// 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 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_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_UTILS_H_