Move ash specific cursor code to CursorManager.

ui/aura/desktop/desktop_cursor_client.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 "ui/aura/desktop/desktop_cursor_client.h"
 
 #include "ui/aura/root_window.h"
 
 namespace aura {
 
 DesktopCursorClient::DesktopCursorClient(aura::RootWindow* window)
     : root_window_(window) {
 }
 
 DesktopCursorClient::~DesktopCursorClient() {
 }
 
 void DesktopCursorClient::SetCursor(gfx::NativeCursor cursor) {
   root_window_->SetCursor(cursor);
 }
 
 void DesktopCursorClient::ShowCursor(bool show) {
   root_window_->ShowCursor(show);
 }
 
 bool DesktopCursorClient::IsCursorVisible() const {
   return root_window_->cursor_shown();
 }
 
+void DesktopCursorClient::SetDeviceScaleFactor(float device_scale_factor) {
+  // TODO(ben|erg): Use the device scale factor set here for the cursor.
+}
+
 }  // namespace aura