Move SkJpegInfo impls to src/pdf

I ran into an accidental issue where there were two implementations of
SkGetJpegInfo at link time after http://review.skia.org/689016 landed.

This moves the implementations to seperate files to make it more
explicit that we only want one at a time depending on if we compiled
in actual JPEG support or not.

Bug: skia:13983
Change-Id: I30d268c995beebed89e9fd30cd6a32bf8088492e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/702138
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
14 files changed