2x Cursor support.

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 6d30a32b17334dbcdaa33ac7e6fcb655126c1c66..13e1ac29c51e5e6b368ba1d1967259142db8c4e9 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -585,6 +585,18 @@ void RootWindow::OnCompositingEnded(ui::Compositor*) {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// RootWindow, ui::LayerDelegate implementation:
+void RootWindow::OnDeviceScaleFactorChanged(
+    float device_scale_factor) {
+  if (cursor_shown_)
+    ShowCursor(false);
+  host_->OnDeviceScaleFactorChanged(device_scale_factor);
+  Window::OnDeviceScaleFactorChanged(device_scale_factor);
+  if (cursor_shown_)
+    ShowCursor(true);
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // RootWindow, private:
 
 void RootWindow::HandleMouseCaptureChanged(Window* old_capture_window) {