exo: Fix multi-display hardware cursor

components/exo/pointer.h

Index: components/exo/pointer.h
diff --git a/components/exo/pointer.h b/components/exo/pointer.h
index 67a12efedb18f4ae457f3afc74bcf01d3dc7bf49..46864ee708d47a26dce1de8612ece53c2cea305b 100644
--- a/components/exo/pointer.h
+++ b/components/exo/pointer.h
@@ -14,6 +14,7 @@
 #include "components/exo/surface_observer.h"
 #include "components/exo/wm_helper.h"
 #include "ui/base/cursor/cursor.h"
+#include "ui/display/display.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_f.h"
@@ -58,6 +59,7 @@ class Pointer : public ui::EventHandler,
 
   // Overridden from WMHelper::CursorObserver:
   void OnCursorSetChanged(ui::CursorSetType cursor_set) override;
+  void OnCursorDisplayChanging(const display::Display& display) override;
 
   // Overridden from SurfaceDelegate:
   void OnSurfaceCommit() override;
@@ -70,18 +72,16 @@ class Pointer : public ui::EventHandler,
   // Returns the effective target for |event|.
   Surface* GetEffectiveTargetForEvent(ui::Event* event) const;
 
-  // Recompute cursor scale and update cursor if scale changed.
-  void UpdateCursorScale();
-
   // Asynchronously update the cursor by capturing a snapshot of |surface_|.
-  void CaptureCursor();
+  void CaptureCursor(bool force);

[reveman, 2017/03/30 07:47:53]

why do we need |force|? can the behavior with force=true be used all the time?

[Dominik Laskowski, 2017/04/05 17:59:25]

No, it should only be used to bypass cursor locking. See pointer.cc for details.

 
   // Called when cursor snapshot has been captured.
-  void OnCursorCaptured(const gfx::Point& hotspot,

[reveman, 2017/03/30 07:47:53]

why not const?

[Dominik Laskowski, 2017/04/05 17:59:25]

Belongs to the dependent CL. Moved.

+  void OnCursorCaptured(gfx::Point hotspot,
+                        bool force,
                         std::unique_ptr<cc::CopyOutputResult> result);
 
-  // Update cursor to reflect the current value of |cursor_|.
-  void UpdateCursor();
+  // If |force| is true, the cursor is updated even if locked.
+  void UpdateCursor(gfx::NativeCursor cursor, bool force);
 
   // The delegate instance that all events are dispatched to.
   PointerDelegate* const delegate_;
@@ -95,17 +95,21 @@ class Pointer : public ui::EventHandler,
   // 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.
+  // The display-dependent scale applied to the cursor.
+  float display_scale_ = 1.0f;
+
+  // The display-independent scale applied to the cursor.
   float cursor_scale_ = 1.0f;
 
+  float device_scale_factor_ = 1.0f;

[reveman, 2017/03/30 07:47:53]

Please add a comment here for consistency.

[Dominik Laskowski, 2017/04/05 17:59:25]

Done.

+
   // The position of the pointer surface relative to the pointer location.
   gfx::Point hotspot_;
 
-  // The current cursor.
-  ui::Cursor cursor_;
+  const std::unique_ptr<aura::Window> cursor_;

[reveman, 2017/03/30 07:47:53]

why do we have to change this? We should avoid using aura::Windows except for
top level shell surfaces so I'm worried about any changes that introduce more
use of them.

[Dominik Laskowski, 2017/04/05 17:59:25]

The snapshot is requested on this layer, because the rotation transform in the
dependent CL is applied to the surface layer, relative to this layer. Also, it
simplifies the code, i.e. the surface window can be unconditionally parented to
this window, because this window is reparented between root windows whenever the
mouse crosses displays.

 
   // Source used for cursor capture copy output requests.
-  const base::UnguessableToken cursor_capture_source_id_;
+  base::UnguessableToken cursor_capture_source_id_;
 
   // Weak pointer factory used for cursor capture callbacks.
   base::WeakPtrFactory<Pointer> cursor_capture_weak_ptr_factory_;