Rework ash::CursorManager into a corewm object, to share code with desktop.

ui/views/widget/desktop_aura/desktop_root_window_host_win.cc

Index: ui/views/widget/desktop_aura/desktop_root_window_host_win.cc
diff --git a/ui/views/widget/desktop_aura/desktop_root_window_host_win.cc b/ui/views/widget/desktop_aura/desktop_root_window_host_win.cc
index 315769a2ffa6a2f34810ed00f6fa233ed62d8cda..9360d909ad58db7a9b34f5b41bce777e6a7898f9 100644
--- a/ui/views/widget/desktop_aura/desktop_root_window_host_win.cc
+++ b/ui/views/widget/desktop_aura/desktop_root_window_host_win.cc
@@ -20,11 +20,12 @@
 #include "ui/native_theme/native_theme_win.h"
 #include "ui/views/corewm/compound_event_filter.h"
 #include "ui/views/corewm/corewm_switches.h"
+#include "ui/views/corewm/cursor_manager.h"
 #include "ui/views/corewm/focus_controller.h"
 #include "ui/views/corewm/input_method_event_filter.h"
 #include "ui/views/ime/input_method_bridge.h"
 #include "ui/views/widget/desktop_aura/desktop_activation_client.h"
-#include "ui/views/widget/desktop_aura/desktop_cursor_client.h"
+#include "ui/views/widget/desktop_aura/desktop_cursor_platform_delegate.h"
 #include "ui/views/widget/desktop_aura/desktop_dispatcher_client.h"
 #include "ui/views/widget/desktop_aura/desktop_drag_drop_client_win.h"
 #include "ui/views/widget/desktop_aura/desktop_focus_rules.h"
@@ -142,8 +143,12 @@ aura::RootWindow* DesktopRootWindowHostWin::Init(
   aura::client::SetDispatcherClient(root_window_,
                                     dispatcher_client_.get());
 
-  cursor_client_.reset(new DesktopCursorClient(root_window_));
-  aura::client::SetCursorClient(root_window_, cursor_client_.get());
+  cursor_client_.reset(
+      new views::corewm::CursorManager(
+          scoped_ptr<corewm::CursorPlatformDelegate>(
+              new views::DesktopCursorPlatformDelegate(root_window_))));
+  aura::client::SetCursorClient(root_window_,
+                                cursor_client_.get());
 
   position_client_.reset(new DesktopScreenPositionClient());
   aura::client::SetScreenPositionClient(root_window_,