Remove WmLookup.

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 1e547ab85c45ef14e4a220f4e3b337a2aa6da200..f17b9a7ff4f43451afc62a32461332619be0d26f 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -162,6 +162,11 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
   // TODO(oshima): move this to |RootWindowController|
   static RootWindowController* GetPrimaryRootWindowController();
 
+  // Returns the RootWindowController for the given display id. If there
+  // is no display for |display_id|, null is returned.
+  static RootWindowController* GetRootWindowControllerWithDisplayId(
+      int64_t display_id);
+
   // Returns all root window controllers.
   // TODO(oshima): move this to |RootWindowController|
   static RootWindowControllerList GetAllRootWindowControllers();