Removes WmRootWindowController::GetShell()

ash/mus/bridge/wm_root_window_controller_mus.cc

Index: ash/mus/bridge/wm_root_window_controller_mus.cc
diff --git a/ash/mus/bridge/wm_root_window_controller_mus.cc b/ash/mus/bridge/wm_root_window_controller_mus.cc
index 6e6faed24c8643f5daedd9932c1da893570e4ac1..a5a3279a65b823e790781c8bc01a16f97030e987 100644
--- a/ash/mus/bridge/wm_root_window_controller_mus.cc
+++ b/ash/mus/bridge/wm_root_window_controller_mus.cc
@@ -73,10 +73,6 @@ bool WmRootWindowControllerMus::HasShelf() {
   return GetShelf() != nullptr;
 }
 
-WmShell* WmRootWindowControllerMus::GetShell() {
-  return shell_;
-}
-
 WmShelf* WmRootWindowControllerMus::GetShelf() {
   return root_window_controller_->wm_shelf();
 }