exo: Replace pointer based stylus and replace with touch based stylus

components/exo/touch.h

Index: components/exo/touch.h
diff --git a/components/exo/touch.h b/components/exo/touch.h
index 5193f782e6787d0300d562272c353326a595aba7..63b37a8caeaa13f266851f29de423f695359d74c 100644
--- a/components/exo/touch.h
+++ b/components/exo/touch.h
@@ -10,6 +10,7 @@
 #include "base/macros.h"
 #include "components/exo/surface_observer.h"
 #include "ui/events/event_handler.h"
+#include "ui/gfx/geometry/point_f.h"
 
 namespace ui {
 class TouchEvent;
@@ -17,6 +18,7 @@ class TouchEvent;
 
 namespace exo {
 class TouchDelegate;
+class TouchStylusDelegate;
 
 // This class implements a client touch device that represents one or more
 // touch devices.
@@ -25,6 +27,10 @@ class Touch : public ui::EventHandler, public SurfaceObserver {
   explicit Touch(TouchDelegate* delegate);
   ~Touch() override;
 
+  // Set delegate for stylus events.
+  void SetStylusDelegate(TouchStylusDelegate* delegate);
+  bool HasStylusDelegate() const;
+
   // Overridden from ui::EventHandler:
   void OnTouchEvent(ui::TouchEvent* event) override;
 
@@ -38,6 +44,9 @@ class Touch : public ui::EventHandler, public SurfaceObserver {
   // The delegate instance that all events are dispatched to.
   TouchDelegate* const delegate_;
 
+  // The delegate instance that all stylus related events are dispatched to.
+  TouchStylusDelegate* stylus_delegate_ = nullptr;
+
   // The current focus surface for the touch device.
   Surface* focus_ = nullptr;