mash: Replace int ShelfIDs with AppLaunchID strings.

ash/wm/window_properties.h

Index: ash/wm/window_properties.h
diff --git a/ash/wm/window_properties.h b/ash/wm/window_properties.h
index 98688f87aa047056f3e18712564bb1cf0eae1d00..1cf6e09468e2ebdc47305c78e327bcedde93f53f 100644
--- a/ash/wm/window_properties.h
+++ b/ash/wm/window_properties.h
@@ -5,10 +5,7 @@
 #ifndef ASH_WM_WINDOW_PROPERTIES_H_
 #define ASH_WM_WINDOW_PROPERTIES_H_
 
-#include <stdint.h>
-
 #include "ash/ash_export.h"
-#include "ash/public/cpp/shelf_types.h"
 #include "ui/base/class_property.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/gfx/geometry/rect.h"
@@ -59,9 +56,6 @@ ASH_EXPORT extern const aura::WindowProperty<gfx::Rect*>* const
 ASH_EXPORT extern const aura::WindowProperty<ui::WindowShowState>* const
     kRestoreShowStateOverrideKey;
 
-// A property key to store the id for a window's shelf item.
-ASH_EXPORT extern const aura::WindowProperty<ShelfID>* const kShelfIDKey;
-
 // Containers with this property (true) are aligned with physical pixel
 // boundary.
 extern const aura::WindowProperty<bool>* const kSnapChildrenToPixelBoundary;