Moves management of transients out of Window

ash/root_window_controller.cc

Index: ash/root_window_controller.cc
diff --git a/ash/root_window_controller.cc b/ash/root_window_controller.cc
index 1af782d079b4a04fcfb9e8af165b6ded86a2a3d9..330b8d4fcfe206bdaa5ae5d5803144216d32f8e9 100644
--- a/ash/root_window_controller.cc
+++ b/ash/root_window_controller.cc
@@ -65,6 +65,7 @@
 #include "ui/views/controls/menu/menu_runner.h"
 #include "ui/views/corewm/capture_controller.h"
 #include "ui/views/corewm/visibility_controller.h"
+#include "ui/views/corewm/window_util.h"
 #include "ui/views/view_model.h"
 #include "ui/views/view_model_utils.h"
 #include "ui/wm/public/easy_resize_window_targeter.h"
@@ -589,7 +590,7 @@ const aura::Window* RootWindowController::GetWindowForFullscreenMode() const {
   while (topmost_window) {
     if (wm::GetWindowState(topmost_window)->IsFullscreen())
       return topmost_window;
-    topmost_window = topmost_window->transient_parent();
+    topmost_window = views::corewm::GetTransientParent(topmost_window);
   }
   return NULL;
 }