Removes ash::mus::RootWindowController

ash/mus/BUILD.gn

Index: ash/mus/BUILD.gn
diff --git a/ash/mus/BUILD.gn b/ash/mus/BUILD.gn
index 339b273c75fe03c8efcfa03f856d370b5942bf86..586bbc8d68a499b9a9f1aea7c5a8c07356cf9c63 100644
--- a/ash/mus/BUILD.gn
+++ b/ash/mus/BUILD.gn
@@ -49,8 +49,6 @@ source_set("lib") {
     "non_client_frame_controller.h",
     "property_util.cc",
     "property_util.h",
-    "root_window_controller.cc",
-    "root_window_controller.h",
     "screen_mus.cc",
     "screen_mus.h",
     "shadow.cc",
@@ -63,6 +61,8 @@ source_set("lib") {
     "shell_delegate_mus.h",
     "system_tray_delegate_mus.cc",
     "system_tray_delegate_mus.h",
+    "top_level_window_factory.cc",
+    "top_level_window_factory.h",
     "wallpaper_delegate_mus.cc",
     "wallpaper_delegate_mus.h",
     "window_manager.cc",
@@ -206,13 +206,13 @@ source_set("unittests") {
     "accelerators/accelerator_controller_unittest.cc",
     "app_launch_unittest.cc",
     "bridge/wm_shell_mus_test_api.h",
-    "root_window_controller_unittest.cc",
     "test/ash_test_impl_mus.cc",
     "test/ash_test_impl_mus.h",
     "test/wm_test_base.cc",
     "test/wm_test_base.h",
     "test/wm_test_helper.cc",
     "test/wm_test_helper.h",
+    "top_level_window_factory_unittest.cc",
     "window_manager_unittest.cc",
   ]