Makes ash/wm/common a library

ash/wm/common/wm_root_window_controller.h

Index: ash/wm/common/wm_root_window_controller.h
diff --git a/ash/wm/common/wm_root_window_controller.h b/ash/wm/common/wm_root_window_controller.h
index 3c7aa500936380ab408c60cb62249a18d1c753c5..f245f36c29d0ed015661f3dda2b8c120e6c3ad26 100644
--- a/ash/wm/common/wm_root_window_controller.h
+++ b/ash/wm/common/wm_root_window_controller.h
@@ -5,9 +5,7 @@
 #ifndef ASH_WM_COMMON_WM_ROOT_CONTROLLER_H_
 #define ASH_WM_COMMON_WM_ROOT_CONTROLLER_H_
 
-#include <stdint.h>
-
-#include "ash/ash_export.h"
+#include "ash/wm/common/ash_wm_common_export.h"
 #include "ash/wm/common/workspace/workspace_types.h"
 #include "ui/views/widget/widget.h"
 
@@ -27,12 +25,10 @@ class WmShelf;
 class WmWindow;
 
 // Provides state associated with a root of a window hierarchy.
-class ASH_EXPORT WmRootWindowController {
+class ASH_WM_COMMON_EXPORT WmRootWindowController {
  public:
   virtual ~WmRootWindowController() {}
 
-  static WmRootWindowController* GetWithDisplayId(int64_t id);
-
   virtual bool HasShelf() = 0;
 
   virtual WmGlobals* GetGlobals() = 0;