Make aura::clients take Window instead of RootWindow

ui/views/widget/desktop_aura/desktop_drop_target_win.cc

Index: ui/views/widget/desktop_aura/desktop_drop_target_win.cc
diff --git a/ui/views/widget/desktop_aura/desktop_drop_target_win.cc b/ui/views/widget/desktop_aura/desktop_drop_target_win.cc
index 5fb109119a419ec2f3cea54f47f74059ad1be4c0..252826aceab7b175629ed5a2d552216c3160ddc2 100644
--- a/ui/views/widget/desktop_aura/desktop_drop_target_win.cc
+++ b/ui/views/widget/desktop_aura/desktop_drop_target_win.cc
@@ -20,7 +20,7 @@ using ui::OSExchangeDataProviderWin;
 
 namespace views {
 
-DesktopDropTargetWin::DesktopDropTargetWin(aura::RootWindow* root_window,
+DesktopDropTargetWin::DesktopDropTargetWin(aura::Window* root_window,
                                            HWND window)
     : ui::DropTargetWin(window),
       root_window_(root_window),
@@ -96,7 +96,7 @@ void DesktopDropTargetWin::Translate(
     DragDropDelegate** delegate) {
   gfx::Point location(position.x, position.y);
   gfx::Point root_location = location;
-  root_window_->ConvertPointFromNativeScreen(&root_location);
+  root_window_->GetRootWindow()->ConvertPointFromNativeScreen(&root_location);
   aura::Window* target_window =
       root_window_->GetEventHandlerForPoint(root_location);
   bool target_window_changed = false;