Auto open and close the palette on an eject event.

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 0cb60c1ba38c64e9ca68970bbc619ce27a97825c..2d362d901d84bec2fab7374b1c5c35537e002eef 100644
--- a/ash/common/system/chromeos/palette/palette_tray.h
+++ b/ash/common/system/chromeos/palette/palette_tray.h
@@ -14,6 +14,8 @@
 #include "ash/common/system/chromeos/palette/palette_tool_manager.h"
 #include "ash/common/system/tray/tray_background_view.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "ui/events/devices/input_device_manager.h"
 
 namespace views {
 class ImageView;
@@ -85,6 +87,9 @@ class ASH_EXPORT PaletteTray : public TrayBackgroundView,
   // Sets the icon to visible if the palette can be used.
   void UpdateIconVisibility();
 
+  // Called when a stylus inserted or removed event is received.
+  void OnStylusStateChanged(ui::StylusState stylus_state);
+
   bool OpenBubble();
   void AddToolsToView(views::View* host);
 
@@ -94,6 +99,8 @@ class ASH_EXPORT PaletteTray : public TrayBackgroundView,
   // Weak pointer, will be parented by TrayContainer for its lifetime.
   views::ImageView* icon_;
 
+  base::WeakPtrFactory<PaletteTray> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(PaletteTray);
 };