Returning null when preview image is not available for AppWidgetProviderInfo

The default application icon generally has a different aspect ratio that a
preview image, and cannot transparently be  used in place of the image.
Returning null will allow the apps to handle the case as they see fit.

Change-Id: Ie6e8e16dd7b4e58b222187a81c62d27eccab45a9
1 file changed