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

ash/common/wm_window_property.h

Index: ash/common/wm_window_property.h
diff --git a/ash/common/wm_window_property.h b/ash/common/wm_window_property.h
index b96903567933ab61f8eca8e8c17b1a4429c590a4..bef6ddb11b9092a716880b3986f680878fd32723 100644
--- a/ash/common/wm_window_property.h
+++ b/ash/common/wm_window_property.h
@@ -25,6 +25,9 @@ enum class WmWindowProperty {
 
   // Type bool. See aura::client:kExcludeFromMruKey for details.
   EXCLUDE_FROM_MRU,
+
+  // Type Rect*. See aura::client:kVKNewBoundsKey for details.
+  VK_NEW_BOUNDS,
 };
 
 }  // namespace ash