Grid content doesn't render when store items contain objects

[guest]

Grid content doesn't render when ItemFileReadStore? input data contains objects inside items, e.g.:

items: [
  { name:'Africa', type:'continent', breaker: {} }
]

To reproduce this just add the breaker from above to the countries.json on test page: Grid using Dojo.Data.

This has been discussed at the forums: Getting grid to work with dojo.data and in the issue: dojo.data.ItemFileReadStore breaks when items contain objects

[BryanForbes]

This is related to #5396 and the grid isn't displaying data because there is no type map. Marking invalid.