Make cursors work on win aura.

ui/views/widget/desktop_root_window_host_win.h

Index: ui/views/widget/desktop_root_window_host_win.h
===================================================================
--- ui/views/widget/desktop_root_window_host_win.h	(revision 157082)
+++ ui/views/widget/desktop_root_window_host_win.h	(working copy)
@@ -11,9 +11,13 @@
 
 namespace aura {
 class DesktopActivationClient;
+class DesktopCursorClient;
 class DesktopDispatcherClient;
 class FocusManager;
+namespace client {
+class ScreenPositionClient;
 }
+}
 
 namespace views {
 class DesktopCaptureClient;
@@ -174,6 +178,13 @@
   aura::RootWindowHostDelegate* root_window_host_delegate_;
   aura::Window* content_window_;
 
+  // In some cases, we set a screen position client on |root_window_|. If we
+  // do, we're responsible for the lifetime.
+  scoped_ptr<aura::client::ScreenPositionClient> position_client_;
+
+  // A simple cursor client which just forwards events to the RootWindow.
+  scoped_ptr<aura::DesktopCursorClient> cursor_client_;
+
   DISALLOW_COPY_AND_ASSIGN(DesktopRootWindowHostWin);
 };