Removes aura dependencies from WindowPositioner

ash/wm/aura/wm_root_window_controller_aura.cc

Index: ash/wm/aura/wm_root_window_controller_aura.cc
diff --git a/ash/wm/aura/wm_root_window_controller_aura.cc b/ash/wm/aura/wm_root_window_controller_aura.cc
index a8ed4cfee530883e3a1c463b8e5780128fec63af..5b4a8890b8d815a53190ab82a8160b097f69b237 100644
--- a/ash/wm/aura/wm_root_window_controller_aura.cc
+++ b/ash/wm/aura/wm_root_window_controller_aura.cc
@@ -5,6 +5,7 @@
 #include "ash/wm/aura/wm_root_window_controller_aura.h"
 
 #include "ash/root_window_controller.h"
+#include "ash/wm/aura/wm_globals_aura.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_property.h"
 
@@ -52,5 +53,9 @@ bool WmRootWindowControllerAura::HasShelf() {
   return root_window_controller_->shelf() != nullptr;
 }
 
+WmGlobals* WmRootWindowControllerAura::GetGlobals() {
+  return WmGlobalsAura::Get();
+}
+
 }  // namespace wm
 }  // namespace ash