Move shelf item tooltip flag from delegate to item.

ash/mus/bridge/wm_window_mus.h

Index: ash/mus/bridge/wm_window_mus.h
diff --git a/ash/mus/bridge/wm_window_mus.h b/ash/mus/bridge/wm_window_mus.h
index 4b88c5ff4126cc23e1789bb587b57a558e7dbe67..06d7714e5b99aa2d949c5f6abf3f728e3e58a8dc 100644
--- a/ash/mus/bridge/wm_window_mus.h
+++ b/ash/mus/bridge/wm_window_mus.h
@@ -98,6 +98,7 @@ class WmWindowMus : public WmWindowAura {
   gfx::Rect GetMinimizeAnimationTargetBoundsInScreen() const override;
   bool IsSystemModal() const override;
   bool GetBoolProperty(WmWindowProperty key) override;
+  void SetBoolProperty(WmWindowProperty key, bool value) override;
   int GetIntProperty(WmWindowProperty key) override;
   WmWindow* GetToplevelWindow() override;
   WmWindow* GetToplevelWindowForFocus() override;