cros: Use runtime stylus detection for ash palette.

ash/common/palette_delegate.h

Index: ash/common/palette_delegate.h
diff --git a/ash/common/palette_delegate.h b/ash/common/palette_delegate.h
index 3d6ad62339313af9e509c6de074626b989799e53..79c22da41b69962ccb7ded69087dab3a88ef77fc 100644
--- a/ash/common/palette_delegate.h
+++ b/ash/common/palette_delegate.h
@@ -20,7 +20,6 @@ class PaletteDelegate {
   using EnableListener = base::Callback<void(bool)>;
   using EnableListenerSubscription =
       base::CallbackList<void(bool)>::Subscription;
-  using OnStylusStateChangedCallback = base::Callback<void(ui::StylusState)>;
 
   virtual ~PaletteDelegate() {}
 
@@ -41,10 +40,6 @@ class PaletteDelegate {
   // See http://crbug.com/647031.
   virtual void SetPartialMagnifierState(bool enabled) = 0;
 
-  // Set callback that is run when a stylus is inserted or removed.
-  virtual void SetStylusStateChangedCallback(
-      const OnStylusStateChangedCallback& on_stylus_state_changed) = 0;
-
   // Returns true if the palette should be automatically opened on an eject
   // event.
   virtual bool ShouldAutoOpenPalette() = 0;