DO NOT MERGE: Decode the input of both setStream and setResource calls first

The size of the input of both setStream and setResource may very big
that system server got oom while handling it, so we try to decode it
first before copying it to the wallpaper path, if the decoding fails, we
treat the input as an invalid input.

Bug: 204087139
Test: Manually set wallpaper, no PDoS observed.
Change-Id: I014cf461954992782b3dfa0dde67c98a572cc770