create struct to hold document and stream for pdf lua object

Bug: skia:
Change-Id: Id2ca3d05a0e0d827a555b827d5188a066725ecbe
Reviewed-on: https://skia-review.googlesource.com/92085
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Mike Reed <reed@google.com>
1 file changed