Make sure stylus tools are always hidden if disabled by the user.

ash/common/system/chromeos/palette/palette_tray.h

Index: ash/common/system/chromeos/palette/palette_tray.h
diff --git a/ash/common/system/chromeos/palette/palette_tray.h b/ash/common/system/chromeos/palette/palette_tray.h
index 65cec2b6d3c5d99a03abbf458030c9470f0dceb7..96f996478c26ebec42fdf2d7529b1ad6faf4c957 100644
--- a/ash/common/system/chromeos/palette/palette_tray.h
+++ b/ash/common/system/chromeos/palette/palette_tray.h
@@ -124,6 +124,9 @@ class ASH_EXPORT PaletteTray : public TrayBackgroundView,
   // instance.
   bool should_block_shelf_auto_hide_ = false;
 
+  // Cached palette enabled/disabled pref value.
+  bool is_palette_enabled_ = true;
+
   // Used to indicate whether the palette bubble is automatically opened by a
   // stylus eject event.
   bool is_bubble_auto_opened_ = false;