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

components/exo/touch.h

 // Copyright 2015 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 COMPONENTS_EXO_TOUCH_H_
 #define COMPONENTS_EXO_TOUCH_H_
 
 #include <vector>
 
 #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;
 }
 
 namespace exo {
 class TouchDelegate;
+class TouchStylusDelegate;
 
 // This class implements a client touch device that represents one or more
 // touch devices.
 class Touch : public ui::EventHandler, public SurfaceObserver {
  public:
   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;
 
   // Overridden from SurfaceObserver:
   void OnSurfaceDestroying(Surface* surface) override;
 
  private:
   // Returns the effective target for |event|.
   Surface* GetEffectiveTargetForEvent(ui::Event* event) const;
 
   // 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;
 
   // Vector of touch points in focus surface.
   std::vector<int> touch_points_;
 
   DISALLOW_COPY_AND_ASSIGN(Touch);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_TOUCH_H_