Enable CursorManager::LockCursor to lock cursor visibility.

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index a1cebe6728db568848e29b89a28815804b6fdc33..8530c645a6ff7f972914d26170aab334ad680a33 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -10,7 +10,6 @@
 
 #include "ash/ash_export.h"
 #include "ash/system/user/login_status.h"
-#include "ash/wm/cursor_delegate.h"
 #include "ash/wm/cursor_manager.h"
 #include "ash/wm/shelf_types.h"
 #include "base/basictypes.h"
@@ -112,7 +111,7 @@ class WorkspaceController;
 //
 // Upon creation, the Shell sets itself as the RootWindow's delegate, which
 // takes ownership of the Shell.
-class ASH_EXPORT Shell : ash::CursorDelegate {
+class ASH_EXPORT Shell {
  public:
   typedef std::vector<aura::RootWindow*> RootWindowList;
   typedef std::vector<internal::RootWindowController*> RootWindowControllerList;
@@ -384,10 +383,6 @@ class ASH_EXPORT Shell : ash::CursorDelegate {
   void InitLayoutManagersForPrimaryDisplay(
       internal::RootWindowController* root_window_controller);
 
-  // aura::CursorManager::Delegate overrides:
-  virtual void SetCursor(gfx::NativeCursor cursor) OVERRIDE;
-  virtual void ShowCursor(bool visible) OVERRIDE;
-
   static Shell* instance_;
 
   // If set before the Shell is initialized, the mouse cursor will be hidden