mash: Convert ShelfWindowWatcher to wm common types

ash/aura/wm_window_aura.h

Index: ash/aura/wm_window_aura.h
diff --git a/ash/aura/wm_window_aura.h b/ash/aura/wm_window_aura.h
index 88ccc1aec80a5760d487103fa2ea05415164fce9..7b69fa137640c1eb9d9e9bf5ca623ded1e83bd52 100644
--- a/ash/aura/wm_window_aura.h
+++ b/ash/aura/wm_window_aura.h
@@ -74,6 +74,8 @@ class ASH_EXPORT WmWindowAura : public WmWindow, public aura::WindowObserver {
   bool IsSystemModal() const override;
   bool GetBoolProperty(WmWindowProperty key) override;
   int GetIntProperty(WmWindowProperty key) override;
+  void SetIntProperty(WmWindowProperty key, int value) override;
+  ShelfItemDetails* GetShelfItemDetails() override;
   const wm::WindowState* GetWindowState() const override;
   WmWindow* GetToplevelWindow() override;
   WmWindow* GetToplevelWindowForFocus() override;