Support processing grouped assets in transformCommand

Summary: Updates a FB-internal type definition.

Reviewed By: yungsters

Differential Revision: D29030001

fbshipit-source-id: 2f885c983d813f68a5ac25f0629523bb38b35491

packages/metro/src/ModuleGraph/types.flow.js

@@ -190,7 +190,7 @@ export type AssetFileVariant = $ReadOnly<{
   filePath: string,
   /**
    * If the asset is an image, this contain the size in physical pixels (ie.
-   * regarless of whether it's a `@2x` or `@3x` version of a smaller image).
+   * scale * logical pixels).
    */
   physicalSize: ?ImageSize,
   /**