Move shelf item tooltip flag from delegate to item.

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 c307a3fd5ba06941d0f8865d13d3aca90e8aa94a..62e8f5a34118d9789a05062e425f128c90a978d9 100644
--- a/ash/aura/wm_window_aura.h
+++ b/ash/aura/wm_window_aura.h
@@ -84,6 +84,7 @@ class ASH_EXPORT WmWindowAura : public WmWindow,
   gfx::Transform GetTargetTransform() const override;
   bool IsSystemModal() const override;
   bool GetBoolProperty(WmWindowProperty key) override;
+  void SetBoolProperty(WmWindowProperty key, bool value) override;
   SkColor GetColorProperty(WmWindowProperty key) override;
   void SetColorProperty(WmWindowProperty key, SkColor value) override;
   int GetIntProperty(WmWindowProperty key) override;