Fix the issue of cursor's device scale factor when using monitors with differnt device scale factor.

ash/ui_controls_ash.cc

 // Copyright (c) 2012 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.
 
 #include "ash/shell.h"
 #include "ash/shell_factory.h"
 #include "ash/wm/coordinate_conversion.h"
 #include "ash/wm/window_properties.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/screen_position_client.h"
@@ skipping 14 matching lines @@
   ui_controls::UIControlsAura* native_ui_control =
       root_window->GetProperty(kUIControlsKey);
   if (!native_ui_control) {
     native_ui_control = aura::CreateUIControlsAura(root_window);
     // Pass the ownership to the |root_window|.
     root_window->SetProperty(kUIControlsKey, native_ui_control);
   }
   return native_ui_control;
 }
 
-// Returns the UIControls object for the RootWindow at the |point| in
-// virtual screen coordinates, and updates the |point| relative to the
+// Returns the UIControls object for the RootWindow at the |point_in_screen|
+// in virtual screen coordinates, and updates the |point| relative to the
 // UIControlsAura's root window.  NULL if there is no RootWindow under
-// the |point|.
-ui_controls::UIControlsAura* GetUIControlsAt(gfx::Point* point) {
-  // If there is a capture events must be relative to it.
-  aura::client::CaptureClient* capture_client =
-      GetCaptureClient(ash::Shell::GetInstance()->GetPrimaryRootWindow());
-  aura::RootWindow* root = NULL;
-  if (capture_client && capture_client->GetCaptureWindow())
-    root = capture_client->GetCaptureWindow()->GetRootWindow();
-  else
-    root = wm::GetRootWindowAt(*point);
+// the |point_in_screen|.
+ui_controls::UIControlsAura* GetUIControlsAt(gfx::Point* point_in_screen) {
+  // TODO(mazda): Support the case passive grab is taken.
+  aura::RootWindow* root = wm::GetRootWindowAt(*point_in_screen);
 
   aura::client::ScreenPositionClient* screen_position_client =
       aura::client::GetScreenPositionClient(root);
   if (screen_position_client)
-    screen_position_client->ConvertPointFromScreen(root, point);
+    screen_position_client->ConvertPointFromScreen(root, point_in_screen);
 
   return GetUIControlsForRootWindow(root);
 }
 
 }  // namespace
 
 class UIControlsAsh : public ui_controls::UIControlsAura {
  public:
   UIControlsAsh() {
   }
@@ skipping 76 matching lines @@
  private:
   DISALLOW_COPY_AND_ASSIGN(UIControlsAsh);
 };
 
 ui_controls::UIControlsAura* CreateUIControls() {
   return new UIControlsAsh();
 }
 
 }  // namespace internal
 }  // namespace ash