exo: Implement support for zwp_stylus_v1 protocol

components/exo/pointer.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_POINTER_H_
 #define COMPONENTS_EXO_POINTER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/exo/surface_delegate.h"
 #include "components/exo/surface_observer.h"
 #include "ui/aura/client/cursor_client_observer.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_f.h"
 
 namespace ui {
 class Event;
 class MouseEvent;
 class MouseWheelEvent;
 }
 
 namespace views {
 class Widget;
 }
 
 namespace exo {
 class PointerDelegate;
+class PointerStylusDelegate;
 class Surface;
 
 // This class implements a client pointer that represents one or more input
 // devices, such as mice, which control the pointer location and pointer focus.
 class Pointer : public ui::EventHandler,
                 public aura::client::CursorClientObserver,
                 public SurfaceDelegate,
                 public SurfaceObserver {
  public:
   explicit Pointer(PointerDelegate* delegate);
   ~Pointer() override;
 
   // Set the pointer surface, i.e., the surface that contains the pointer image
   // (cursor). The |hotspot| argument defines the position of the pointer
   // surface relative to the pointer location. Its top-left corner is always at
   // (x, y) - (hotspot.x, hotspot.y), where (x, y) are the coordinates of the
   // pointer location, in surface local coordinates.
   void SetCursor(Surface* surface, const gfx::Point& hotspot);
 
+  // Set delegate for stylus events.
+  void SetStylusDelegate(PointerStylusDelegate* delegate);
+
   // Overridden from ui::EventHandler:
   void OnMouseEvent(ui::MouseEvent* event) override;
   void OnScrollEvent(ui::ScrollEvent* event) override;
 
   // Overridden from aura::client::CursorClientObserver:
   void OnCursorSetChanged(ui::CursorSetType cursor_set) override;
 
   // Overridden from SurfaceDelegate:
   void OnSurfaceCommit() override;
   bool IsSurfaceSynchronized() const override;
 
   // Overridden from SurfaceObserver:
   void OnSurfaceDestroying(Surface* surface) override;
 
  private:
   // Creates the |widget_| for pointer.
   void CreatePointerWidget();
 
   // Updates the scale of the cursor with the latest state.
   void UpdateCursorScale();
 
   // Returns the effective target for |event|.
   Surface* GetEffectiveTargetForEvent(ui::Event* event) const;
 
   // The delegate instance that all events are dispatched to.
   PointerDelegate* const delegate_;
 
+  // The delegate instance that all stylus related events are dispatched to.
+  PointerStylusDelegate* stylus_delegate_ = nullptr;
+
   // The widget for the pointer cursor.
   std::unique_ptr<views::Widget> widget_;
 
   // The current pointer surface.
   Surface* surface_ = nullptr;
 
   // The current focus surface for the pointer.
   Surface* focus_ = nullptr;
 
   // The location of the pointer in the current focus surface.
   gfx::PointF location_;
 
   // The scale applied to the cursor to compensate for the UI scale.
   float cursor_scale_ = 1.0f;
 
   // The position of the pointer surface relative to the pointer location.
   gfx::Point hotspot_;
 
+  // The current pointer type.
+  ui::EventPointerType pointer_type_;
+
+  // The current pointer tilt.
+  gfx::Vector2dF tilt_;
+
+  // The current pointer force.
+  float force_;
+
   DISALLOW_COPY_AND_ASSIGN(Pointer);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_POINTER_H_