Add window property for restore bounds when virtual keyboard is enabled.

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 449c74a695a9070b6528252f63faf625d440722a..1582ad25ff7d1ae640848e16505d782aef331b78 100644
--- a/ash/aura/wm_window_aura.h
+++ b/ash/aura/wm_window_aura.h
@@ -79,6 +79,7 @@ class ASH_EXPORT WmWindowAura : public WmWindow,
   bool GetBoolProperty(WmWindowProperty key) override;
   int GetIntProperty(WmWindowProperty key) override;
   void SetIntProperty(WmWindowProperty key, int value) override;
+  gfx::Rect* GetRectProperty(WmWindowProperty key) override;
   ShelfItemDetails* GetShelfItemDetails() override;
   void SetShelfItemDetails(const ShelfItemDetails& details) override;
   void ClearShelfItemDetails() override;