Add extras to AFD, send orientation metadata.

AssetFileDescriptor augments a ParcelFileDescriptor with details
about how it should be interpreted, so extend it to support a Bundle
of extras.  Then use these extras to share thumbnail orientation
metadata.

The raw image data of EXIF thumbnails matches the orientation of
the enclosing image, but the thumbnail data doesn't repeat the EXIF
flags.  This meant that receivers of openDocumentThumbnail() would
get an image that needed to be transformed, but without enough
context to actually transform it.

Instead of transforming and recompressing the image on the fly on
the provider side, send a transformation hint that the receiver
side can interpret.

Bug: 11205688
Change-Id: Ibc5a7ad002377a55e6ffcb5ac5c8829841002e06