Moves ash/wm/common back into ash

ash/wm/common/wm_root_window_controller_observer.h

Index: ash/wm/common/wm_root_window_controller_observer.h
diff --git a/ash/wm/common/wm_root_window_controller_observer.h b/ash/wm/common/wm_root_window_controller_observer.h
index 0f8a64e534227206f6f74bf2153096ca06e29317..8e9e916fa14f9cc6510e184a244161166ee7db2a 100644
--- a/ash/wm/common/wm_root_window_controller_observer.h
+++ b/ash/wm/common/wm_root_window_controller_observer.h
@@ -5,14 +5,14 @@
 #ifndef ASH_WM_COMMON_WM_ROOT_WINDOW_CONTROLLER_OBSERVER_H_
 #define ASH_WM_COMMON_WM_ROOT_WINDOW_CONTROLLER_OBSERVER_H_
 
-#include "ash/wm/common/ash_wm_common_export.h"
+#include "ash/ash_export.h"
 
 namespace ash {
 namespace wm {
 
 class WmWindow;
 
-class ASH_WM_COMMON_EXPORT WmRootWindowControllerObserver {
+class ASH_EXPORT WmRootWindowControllerObserver {
  public:
   virtual void OnWorkAreaChanged() {}
   virtual void OnFullscreenStateChanged(bool is_fullscreen) {}