Remove #if MOBILE for GridView deletion-related properties, and add comment that these are supported on iOS only. Removing the #if allows client code to not require similar conditional compilation.
Prepare TextureBrush tests for D2D. They don't run yet because of bitmap issues.
GridView: make the Delete confirmation title a function of the item.
Grid view: the delete item handler should take care of removing the item from the data source, so removed this logic from GridViewHandler.